Fireproof safe, and living in an area where the fire department would be able to get the fire under control fast enough that I would hopefully not need 1/10th of the capability of that safe.
Edit: also, if your house burns down, won’t you probably have your keys on you if you’re not home?
Although these keys are intended to be stored on a keychain, I don't know of anyone that actually uses them that way. If you work remotely, there's just no need to have your keys on you most of the time. One of my keys is a 5C Nano and it just sits in the laptop all day long. So, if my house burns, I'm losing any keys in the house along with it.
As for a fireproof safe, I do have one, but they're rated for X hours and degrade over time. I should probably get a new one.
Edit: also, if your house burns down, won’t you probably have your keys on you if you’re not home?