My toyota 4AFE engine was seized while driving without overheating.

The temperature was normal and no coolant leaks or oil leaks noticed. The engine showed no major signs of failure except a very minor shake only when idling.

I heard a bit of screeching from the pulleys before it got seized which I mistakenly thought as a lose belt because I repaired the air condition compressor a couple of days ago  

All 4 cylinders were showing 200psi compression a month before it got seized.

No white or black smoke from exhaust pipes even on higher RPMs. The milage was around 360000km and I used Valvoline hight milage engine oil all the time with some Liqui Moli oil additives.

I am still surprised how it is seized. 

Is it possible for this kind of seizing to happen?