It's a case of hunting through scrap yards...
The door locks are the same on the K10 and K11 as are various other parts (window winders etc...) However the ignition barrel in not the same and incorporates a small push button to release the key. The nissan sunny's and i think bluebirds from the same era also used the same ignition barrel as the k10.
If you open your glovebox you should find a small sticker with your ignition key number on it, if you give this number to a dealer they can get you a barrel to fit your key. Dealers aren't always expensive, it would only cost £15 to get a genuine NATS key made for a k11 micra so they might be good on price if you can't find a 2nd hand unit.