There are not many emergencies I can imagine where it is necessary to remove the belt.
If they must, put you in an MRI scanner or insert a catheter into you in the ICU.
You must always have a key with you, but it must be impossible for you to use it.
Otherwise, the whole idea of a locked belt is pointless.
I have my emergency key fixed with a cable tie to this metal triangle on my back.
With a mirror and scissors, I can't get it, so it's a safe place for "horny" moments.