Stazo uses a disc detainer lock that is difficult to finesse.
Deviant Ollam on removal
of broken keys:
LPL on disc detainer locks and how to pick them:
A pick may be helpful for loosening stuck tumblers.
If you have a second key, or can order a second key from Stazo, and get the one you broke out of the keyway, that might be your best bet. I would apply some vibration to the lock using an air impact hammer or similar, or maybe some tapping with a light hammer, to try to loosen internal parts
Otherwise you're going to have to cut it off or drill it and either way that will be no picnic