I’ve locked my keys in my car a handful times. The first few times, I knew someone that had a “Slim Jim”. I’ve also had to call AAA – how embarrassing.
But, if you’re a AAA member, you can request a credit card key that’ll fit in your wallet[1. Don’t forget to present your membership card.].
Note: It can only be used to open your car door, which doesn’t matter because you’re just retrieving your locked keys inside the car.