diff --git a/backend/app/models/l1_walk_session.py b/backend/app/models/l1_walk_session.py
index 9eb09edd..072fd587 100644
--- a/backend/app/models/l1_walk_session.py
+++ b/backend/app/models/l1_walk_session.py
@@ -128,6 +128,7 @@ class L1WalkSession(Base):
         DateTime(timezone=True),
         default=lambda: datetime.now(timezone.utc),
         onupdate=lambda: datetime.now(timezone.utc),
+        index=True,
     )
     resolved_at: Mapped[Optional[datetime]] = mapped_column(
         DateTime(timezone=True), nullable=True,