diff --git a/store/app/crud/base.py b/store/app/crud/base.py
index 423fd87a..2c405f9e 100644
--- a/store/app/crud/base.py
+++ b/store/app/crud/base.py
@@ -359,7 +359,7 @@ async def _get_unique_item_from_secondary_index(
         item_class: type[T],
         throw_if_missing: bool = False,
     ) -> T | None:
-        if secondary_index_name not in item_class.model_fields:
+        if secondary_index_name not in item_class.model_json_schema()["properties"]:
             raise InternalError(f"Field '{secondary_index_name}' not in model {item_class.__name__}")
         items = await self._get_items_from_secondary_index(
             secondary_index_name,