Don't know anything about the Ryobi, but the old craftsman power tools used a very similar key. What has worked for me in the past is to buy a cheap toggle switch and unwire the old switch and wire in the new toggle. It won't be as 'child proof' as with the key, but I never liked a plastic piece as an interlock anyway. They tend to get bumped and fall out mid cut or get lost, wasting time on a
project while a new one is sourced. It is maddening to waste a day or a week because a 5 cent piece of plastic is keeping me from using my tool. That inconvenience is to keep Ryobi's lawyers happy at night. Does nothing for me.
I also don't have young curious hands running around my shop either. Choose wisely.