Samsung SCH-U520

Does anyone know of a fast way to lock the Samsung SCH-u520 phone? I know I can press 9, 5, 3, enter my code, press OK for the Lock options, press up to go to Lock, and press OK. Or I can set it up so that it is locked every time I turn the phone on. But I need to keep my phone locked whenever it's not in use and it seems like a hassle to have to turn the phone off and back on every time I use it just to get it locked. Does anyone know of a quicker way?
Thanks in advance.