I had this one last night on a production environment:

"Connection Timeout Expired. The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement. This could be because the pre-login handshake failed or the server was unable to respond back in time. The duration spent while attempting to connect to this server was - [Pre-Login] initialization=0; handshake=15012;System.ComponentModel.Win32Exception (0x80004005): The wait operation timed out"

DECLARE @Numero Int

SET @Numero=1

SELECT Admin.* FROM Admin (NOLOCK) WHERE Admin.Numero=@Numero

There is only one record in that table. So, it is not related to the query itself.