text: Title: jwt_optional does not give None, instead the old token
  Body: ```
  @api.route("/")
  class Payment(Resource):
  
      @jwt_optional
      @api.header("Authorization", "access token", required=False)
      @api.doc(payment_fields)
      @api.expect(payment_fields)
      def post(self):
  
          username = get_jwt_identity()
  ```
  
  This endpoint are jwt optional, which can be either identify with access token or email alone. This endpoint are use for both make payment or first registration. 
  
  I first logged in with an account, then i logged out and clear my browser cookie and local storage which I use to store access token, then when I try to register it appear my old username instead of `None`. But everytime when I restart my backend it appear back to `None` again. Are there way to stop the cache?