Aqua-stats do fail, and the amp draw seems normal. I have not seen that kind or 'frying' of the terminal, but that is why we add an overheat aquastat 4006A or a 6006A.
One word about shutting the switch off......that normally would shut down the circulator also, so take that into consideration if you are trying to 'scrub' heat off a hot boiler.
The relay comment Freddy makes are VERY true. The KISS philosophy works best here, and relays sure do protect the system controls from a motor short or the like.
I would suggest you lower the 230 setting to 200 max, just as an added safety. You know the deal....it will never happen again in three lifetimes.....but....
I assume you can't find any oil holes on the motor either....you, they are all permanently lubed. There won't be 25 year old motors anymore.....simply not going to happen. Part of the PM program for any unit.
The smaller stokers seem to go about 5 to 8 years on their motors.....so one motor doing all the work that lasts for 20 years is a good thing.
Controls are a different matter.....they seem to last forever; perhaps you just got a bad one, OR something else in the circuitry caused an overload (hint: I'd look at that situation before I add the new aquastat.....$$130 bucks is expensive to waste)
Good luck, please let us know how it turns out. The contact rating for your control aquastat is more THAT ADEQUATE for the load of an AA130.