diff --git a/cetmix_tower_server/models/cx_tower_key.py b/cetmix_tower_server/models/cx_tower_key.py
index 11820946..e7ed33d6 100644
--- a/cetmix_tower_server/models/cx_tower_key.py
+++ b/cetmix_tower_server/models/cx_tower_key.py
@@ -60,10 +60,7 @@ def _compute_key_ref_complete(self):
             if rec.key_ref:
                 key_prefix = self._compose_key_prefix(rec.key_type)
                 if key_prefix:
-                    rec.key_ref_complete = "#!cxtower.%(prefix)s.%(ref)s!#" % {
-                        "prefix": key_prefix,
-                        "ref": rec.key_ref,
-                    }
+                    rec.key_ref_complete = f"#!cxtower.{key_prefix}.{rec.key_ref}!#"
                 else:
                     rec.key_ref_complete = None
             else: