diff --git a/redash/models/__init__.py b/redash/models/__init__.py
index a0b0508563..91ddd91ee3 100644
--- a/redash/models/__init__.py
+++ b/redash/models/__init__.py
@@ -578,7 +578,8 @@ def past_scheduled_queries(cls):
         return [
             query
             for query in queries
-            if query.schedule["until"] is not None
+            if "until" in query.schedule
+            and query.schedule["until"] is not None
             and pytz.utc.localize(datetime.datetime.strptime(query.schedule["until"], "%Y-%m-%d")) <= now
         ]