Keypause

Keypause is a Mac menu bar app that locks every key while you clean your keyboard, then hands control back when the timer runs out. Shortcuts, function keys and media keys are all disabled, while the mouse and trackpad keep working so you can keep using the machine.

A small countdown appears without taking focus, so a video keeps playing, and the menu bar keycap slowly wakes from night into sunrise as the timer goes. You can start it from anywhere with a hotkey, from the menu or from Terminal, and it always ends on its own.