Batman Vol.1 #587
It's Commissioner Gordon's birthday, and the GCPD throw him a party at the local pub. After kindly receiving gifts from his officers, Gordon reveals he has brought gifts for them, himself, as well. He withdraws a pocketful of handcuff keys and passes them out, and after the initial curiosity, gives his explanation.
Number One, as a cop, handcuff keys are always the one thing you can never find when you need them.
Estimated Condition: VF/NM