diff --git a/zarr/_storage/store.py b/zarr/_storage/store.py
index 2fe5c49506..9f66934aaf 100644
--- a/zarr/_storage/store.py
+++ b/zarr/_storage/store.py
@@ -214,7 +214,7 @@ def _valid_key(self, key: str) -> bool:
         0-9, or in the set /.-_ it will return True if that's the case, False
         otherwise.
         """
-        if not isinstance(key, str) or not key.isascii():
+        if not isinstance(key, str) or not key.isascii():  # type: ignore[redundant-expr]
             return False
         if set(key) - self._valid_key_characters:
             return False
diff --git a/zarr/storage.py b/zarr/storage.py
index 7f01b6223a..3a40f11385 100644
--- a/zarr/storage.py
+++ b/zarr/storage.py
@@ -2556,7 +2556,7 @@ def _cache_value(self, key: Path, value):
         value_size = buffer_size(value)
         # check size of the value against max size, as if the value itself exceeds max
         # size then we are never going to cache it
-        if self._max_size is None or value_size <= self._max_size:
+        if self._max_size is None or value_size <= self._max_size:  # type: ignore[redundant-expr]
             self._accommodate_value(value_size)
             self._values_cache[key] = value
             self._current_size += value_size