How to turn LCD off and only allow back on with predefined keystroke?

Is there a simple method in any programming language that I can use to turn off my LCD monitor but only allow the monitor to come back on if I press a certain key? I downloaded an LCD off application but the problem is that when I am away from the computer and my mouse moves the monitor comes back on. This means my monitor could be on for hours without me knowing it and burn up the screen. That is why I would like to make the LCD off application only allow for the screen to turn on after pressing a predefined key.