diff --git a/lib/token-types/bearer-token-type.js b/lib/token-types/bearer-token-type.js
index 373d8731..a0c836aa 100644
--- a/lib/token-types/bearer-token-type.js
+++ b/lib/token-types/bearer-token-type.js
@@ -57,11 +57,9 @@ class BearerTokenType {
       object.scope = this.scope;
     }
 
-    for (const key in this.customAttributes) {
-      if ( Object.prototype.hasOwnProperty.call(this.customAttributes, key) ) {
-        object[key] = this.customAttributes[key];
-      }
-    }
+    Object.keys(this.customAttributes).forEach((key) => {
+      object[key] = this.customAttributes[key];
+    });
     return object;
   }
 }