I have had this happen several times over the years.

A local Discount Tire or Belletire (any big chain place, or even a mom-and-pop store for that matter) sometimes have universal keys that can TRY.

If not, they can break them off. They usually charge $10-$20 per rim... but if you can't find the key, you have no other choice.

Also, I'd try a Chrysler dealership to see if they have a master (as previously stated)