Parenthesis do not match. Try this:
If Exists(Select UserId from tblResetPasswordRequests where Id =@GUID)
Edit
It occurs to me that your code is too procedural. It's better you avoid that with SQL. Moreover having logic in database is usually not recommended. You should simply query the data e.g.:
Select count(UserId) from tblResetPasswordRequests where Id =@GUID
and then evaluate the result in your application.