If your MCU is short-circuited, it will be hot to the touch after you power on.
During normal operation, nothing on the MCU board (including the power regulator) should get hot. So if you use your finger to touch the components while powered on you should get a sense of whether there are any possible shorts.
This test however can not tell you whether an input pin is shorted since the current draw is very small and it wouldn't produce any heat or affect the supply voltage.