The 60W rating of the MOSFET only applies for a millisecond or a microsecond.
You have to decide how much heatsink you give to it and then go through the calculations of degrees per watt. With a SMD device on a regular PCB with no heatsink, you may see 110 degrees per watt. That means that it will burn out if you give it more than 1.5 watts power dissipation continuously.