In flight you rely on your PLOG, and especially on the MSA if you have to descent and if the weather is not so good.
But what MSA parameters had you chosen when you prepared your flight?
There is no way to check once in flight with your printed plog. You might have changed the definition and forgot about it, or you can, as I do, use 2 definitions, a VFR minimum height one, and an IFR one, depending on the type of flight.
A reminder on the plog of the parameters used to calculate the MSA could save your life.