diff --git a/services/storage/src/simcore_service_storage/modules/celery/client.py b/services/storage/src/simcore_service_storage/modules/celery/client.py
index 23388d71d549..1b491ff197e8 100644
--- a/services/storage/src/simcore_service_storage/modules/celery/client.py
+++ b/services/storage/src/simcore_service_storage/modules/celery/client.py
@@ -133,15 +133,15 @@ def get_task_status(
     def _get_completed_task_uuids(self, task_context: TaskContext) -> set[TaskUUID]:
         search_key = _CELERY_TASK_META_PREFIX + _build_task_id_prefix(task_context)
         backend_client = self._celery_app.backend.client
-        if hasattr(backend_client, "keys") and (
-            keys := backend_client.keys(f"{search_key}*")
-        ):
-            return {
-                TaskUUID(
-                    f"{key.decode(_CELERY_TASK_ID_KEY_ENCODING).removeprefix(search_key + _CELERY_TASK_ID_KEY_SEPARATOR)}"
-                )
-                for key in keys
-            }
+        if hasattr(backend_client, "keys"):
+            if keys := backend_client.keys(f"{search_key}*"):
+                return {
+                    TaskUUID(
+                        f"{key.decode(_CELERY_TASK_ID_KEY_ENCODING).removeprefix(search_key + _CELERY_TASK_ID_KEY_SEPARATOR)}"
+                    )
+                    for key in keys
+                }
+            return set()
         if hasattr(backend_client, "cache"):
             # NOTE: backend used in testing. It is a dict-like object
             found_keys = set()