diff --git a/lib/ex_oauth2_provider/mixin/expirable.ex b/lib/ex_oauth2_provider/mixin/expirable.ex
index 3ac8ceb8..d0cf3eaa 100644
--- a/lib/ex_oauth2_provider/mixin/expirable.ex
+++ b/lib/ex_oauth2_provider/mixin/expirable.ex
@@ -42,7 +42,7 @@ defmodule ExOauth2Provider.Mixin.Expirable do
   def is_expired?(%{expires_in: nil, inserted_at: _}), do: false
   def is_expired?(%struct{expires_in: expires_in, inserted_at: inserted_at}) do
     now  = SchemaHelpers.__timestamp_for__(struct, :inserted_at)
-    type = now.__struct__()
+    type = now.__struct__
 
     inserted_at
     |> type.add(expires_in, :second)