diff --git a/pyupgrade/_plugins/typing_pep604.py b/pyupgrade/_plugins/typing_pep604.py
index 85aee7c1..155d44c4 100644
--- a/pyupgrade/_plugins/typing_pep604.py
+++ b/pyupgrade/_plugins/typing_pep604.py
@@ -144,20 +144,18 @@ def visit_Subscript(
     if not _supported_version(state):
         return
 
-    # prevent rewriting forward annotations (unless they will be dequoted)
-    has_forward_annotation = (
-        (sys.version_info >= (3, 9) and _any_arg_is_str(node.slice)) or
-        (
-            sys.version_info < (3, 9) and
-            isinstance(node.slice, ast.Index) and
-            _any_arg_is_str(node.slice.value)
+    # don't rewrite forward annotations (unless we know they will be dequoted)
+    if 'annotations' not in state.from_imports['__future__']:
+        has_forward_annotation = (
+            (sys.version_info >= (3, 9) and _any_arg_is_str(node.slice)) or
+            (
+                sys.version_info < (3, 9) and
+                isinstance(node.slice, ast.Index) and
+                _any_arg_is_str(node.slice.value)
+            )
         )
-    )
-    if (
-        has_forward_annotation
-        and 'annotations' not in state.from_imports['__future__']
-    ):
-        return
+        if has_forward_annotation:
+            return
 
     if is_name_attr(
             node.value,