Do you have any cooling or heatsink on the MOSFET?
The on resistance of the MOSFET will cause it to dissipate ~500-600mW of heat. The MOSFET has a thermal resistance of junction to ambient of about 62°C/W if it is soldered to the PCB with the minimum footprint's worth of copper. This value will be worse if it is just soldered using wires, as it doesn't have the copper of the PCB to sink heat into.
Unfortunately, it also has a very high positive resistance temperature coefficient. If you look at the datasheet, the resistance can climb as high as 2.3 Ω as it heats up.
As the temperature increases, so does the resistance. This increases the power dissipation in the FET, which makes the temperature increase even more, resulting in yet higher on resistance, and a positive feedback loop is formed.
This is known as thermal runaway.
Using Infineon's level 3 thermal SPICE model for that FET, I simulated your circuit using 65°C/W of thermal resistance and it does indeed go into thermal runaway and, well, burn up. The 'voltage' on the vertical axis is actually degrees of temperature rise above ambient. It hits 150°C pretty fast.
The problem will be even worse with the other FET you tried given that it has almost double the resistance at 25°C and similar thermal resistance.
Yes, 600mW is well below the maximum power dissipation rating of both MOSFETs, but it is important to understand what that spec actually means.
That is the maximum power the MOSFET can dissipate assuming there is no additional thermal resistance from the case to ambient, and only the thermal resistance of the junction to the case, and the case is kept at 25°C. In other words, it is the power the MOSFET can dissipate if it has a thermally perfect interface with an infinitely large heatsink with infinite thermal conductivity.
The maximum junction temperature is 150°C. The junction to case thermal resistance is 2.5°C/W. 50W * 2.5°C/W + 25°C (case temp) = 150°C.
For the package those FETs are in, they will struggle to dissipate even 1W of heat by itself. The data sheet says that the drain must be soldered to a 40mm x 40mm solid 2oz copper pour on a 1.6mm FR4 1 layer PCB just to lower the thermal resistance to 35°C/W.
If you properly cool the MOSFET, or choose one that will dissipate less power and doesn't have such a poor positive resistance temperature coefficient, that will solve your problem.
If you lower the junction to ambient thermal resistance to 32°C/W (using 40mm x 40 mm of 2oz copper on a PCB), it'll still get pretty toasty but nothing it wasn't made to handle. More importantly, it will reach a steady temperature and not keep getting hotter and hotter: