They are 2 different things. The ad crate key was a crate that was never made while the yellow voter key was the original vote key color
They have been unobtainable for quite some time now from my understanding, not sure exactly when the keys were changed but I believe sometime around the starting of this new server.
Yellow vote crate keys are from the first week of 2018 then they were changed. I have two it’s a very exclusive item price is sellers opinion since there isn’t enough in circulation to get an average from the community.