I know it sounds like a cliché,
but compromise is KEY.
The Big Bang Theory Season 10, Episode 4
but there's a
lock for every KEY.
The Big Bang Theory Season 5, Episode 6
Sorry. I used my KEY.
The Big Bang Theory Season 12, Episode 15
Point of inquiry: Why did you
put your car KEY in the door lock?
The Big Bang Theory Season 2, Episode 3
A decryption KEY needed
only in the unlikely event
Westworld Season 2, Episode 7