No you can't put mains power on a mkxxx heated bed for a number of reasons, the resistance is too low and will blow the track on the pcb / alu plate, the insulation isn't made for mains, it may lead to unsafe situations. The psu you linked to is most likely too weak depending on the resistance you needcsomething like 12-15 amps psu, but that's only for a 200x200mm heated bed. For 300x300 you'd need a 600 to 750W of power, so a silicone heater would be better and these can be powered by mains.
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Kind regards
Imqqmi
NFAN CoreXY printer:
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reprap.org]