diff --git a/processing/src/main/java/org/apache/druid/query/groupby/GroupByQuery.java b/processing/src/main/java/org/apache/druid/query/groupby/GroupByQuery.java
index 8162f2455fe..b4fb0756cde 100644
--- a/processing/src/main/java/org/apache/druid/query/groupby/GroupByQuery.java
+++ b/processing/src/main/java/org/apache/druid/query/groupby/GroupByQuery.java
@@ -345,6 +345,8 @@ public class GroupByQuery extends BaseQuery<ResultRow>
   /**
    * If this query has a single universal timestamp, return it. Otherwise return null.
    *
+   * If {@link #getIntervals()} is empty, there are no results (or timestamps) so this method returns null.
+   *
    * This method will return a nonnull timestamp in the following two cases:
    *
    * 1) CTX_KEY_FUDGE_TIMESTAMP is set (in which case this timestamp will be returned).
@@ -715,7 +717,12 @@ public class GroupByQuery extends BaseQuery<ResultRow>
     if (!timestampStringFromContext.isEmpty()) {
       return DateTimes.utc(Long.parseLong(timestampStringFromContext));
     } else if (Granularities.ALL.equals(granularity)) {
-      final DateTime timeStart = getIntervals().get(0).getStart();
+      final List<Interval> intervals = getIntervals();
+      if (intervals.isEmpty()) {
+        // null, the "universal timestamp" of nothing
+        return null;
+      }
+      final DateTime timeStart = intervals.get(0).getStart();
       return granularity.getIterable(new Interval(timeStart, timeStart.plus(1))).iterator().next().getStart();
     } else {
       return null;
diff --git a/sql/src/main/java/org/apache/druid/sql/calcite/filtration/CombineAndSimplifyBounds.java b/sql/src/main/java/org/apache/druid/sql/calcite/filtration/CombineAndSimplifyBounds.java
index 971ba1620a2..7b4f4b669ec 100644
--- a/sql/src/main/java/org/apache/druid/sql/calcite/filtration/CombineAndSimplifyBounds.java
+++ b/sql/src/main/java/org/apache/druid/sql/calcite/filtration/CombineAndSimplifyBounds.java
@@ -27,6 +27,7 @@ import org.apache.druid.java.util.common.ISE;
 import org.apache.druid.query.filter.AndDimFilter;
 import org.apache.druid.query.filter.BoundDimFilter;
 import org.apache.druid.query.filter.DimFilter;
+import org.apache.druid.query.filter.FalseDimFilter;
 import org.apache.druid.query.filter.NotDimFilter;
 import org.apache.druid.query.filter.OrDimFilter;
 
@@ -52,7 +53,10 @@ public class CombineAndSimplifyBounds extends BottomUpTransform
   @Override
   public DimFilter process(DimFilter filter)
   {
-    if (filter instanceof AndDimFilter) {
+    if (filter instanceof FalseDimFilter) {
+      // we might sometimes come into here with just a false from optimizing impossible conditions
+      return filter;
+    } else if (filter instanceof AndDimFilter) {
       final List<DimFilter> children = getAndFilterChildren((AndDimFilter) filter);
       final DimFilter one = doSimplifyAnd(children);
       final DimFilter two = negate(doSimplifyOr(negateAll(children)));
@@ -130,15 +134,25 @@ public class CombineAndSimplifyBounds extends BottomUpTransform
     // Group Bound filters by dimension, extractionFn, and comparator and compute a RangeSet for each one.
     final Map<BoundRefKey, List<BoundDimFilter>> bounds = new HashMap<>();
 
+    // all and/or filters have at least 1 child
+    boolean allFalse = true;
     for (final DimFilter child : newChildren) {
       if (child instanceof BoundDimFilter) {
         final BoundDimFilter bound = (BoundDimFilter) child;
         final BoundRefKey boundRefKey = BoundRefKey.from(bound);
         final List<BoundDimFilter> filterList = bounds.computeIfAbsent(boundRefKey, k -> new ArrayList<>());
         filterList.add(bound);
+        allFalse = false;
+      } else {
+        allFalse &= child instanceof FalseDimFilter;
       }
     }
 
+    // short circuit if can never be true
+    if (allFalse) {
+      return Filtration.matchNothing();
+    }
+
     // Try to simplify filters within each group.
     for (Map.Entry<BoundRefKey, List<BoundDimFilter>> entry : bounds.entrySet()) {
       final BoundRefKey boundRefKey = entry.getKey();
diff --git a/sql/src/test/java/org/apache/druid/sql/calcite/CalciteQueryTest.java b/sql/src/test/java/org/apache/druid/sql/calcite/CalciteQueryTest.java
index 656ae472315..f91e7832836 100644
--- a/sql/src/test/java/org/apache/druid/sql/calcite/CalciteQueryTest.java
+++ b/sql/src/test/java/org/apache/druid/sql/calcite/CalciteQueryTest.java
@@ -96,6 +96,7 @@ import org.apache.druid.query.groupby.orderby.OrderByColumnSpec.Direction;
 import org.apache.druid.query.lookup.RegisteredLookupExtractionFn;
 import org.apache.druid.query.ordering.StringComparators;
 import org.apache.druid.query.scan.ScanQuery;
+import org.apache.druid.query.spec.MultipleIntervalSegmentSpec;
 import org.apache.druid.query.topn.DimensionTopNMetricSpec;
 import org.apache.druid.query.topn.InvertedTopNMetricSpec;
 import org.apache.druid.query.topn.NumericTopNMetricSpec;
@@ -5214,6 +5215,29 @@ public class CalciteQueryTest extends BaseCalciteQueryTest
     );
   }
 
+  @Test
+  public void testGroupByWithImpossibleTimeFilter() throws Exception
+  {
+    // this gets optimized into 'false'
+    testQuery(
+        "SELECT dim1, COUNT(*) FROM druid.foo\n"
+        + "WHERE FLOOR(__time TO DAY) = TIMESTAMP '2000-01-02 01:00:00'\n"
+        + "OR FLOOR(__time TO DAY) = TIMESTAMP '2000-01-02 02:00:00'\n"
+        + "GROUP BY 1",
+        ImmutableList.of(
+            GroupByQuery.builder()
+                        .setDataSource(CalciteTests.DATASOURCE1)
+                        .setInterval(new MultipleIntervalSegmentSpec(ImmutableList.of()))
+                        .setDimensions(dimensions(new DefaultDimensionSpec("dim1", "d0")))
+                        .setAggregatorSpecs(aggregators(new CountAggregatorFactory("a0")))
+                        .setGranularity(Granularities.ALL)
+                        .setContext(QUERY_CONTEXT_DEFAULT)
+                        .build()
+        ),
+        ImmutableList.of()
+    );
+  }
+
   @Test
   public void testGroupByOneColumnWithLiterallyFalseFilter() throws Exception
   {
@@ -17058,5 +17082,4 @@ public class CalciteQueryTest extends BaseCalciteQueryTest
         ).build()
     );
   }
-
 }