Don't lose sleep over it ...

The voltage rating relates to its ability to function and extinguish arcs when it opens. When 2 conductors are close enough (but not touching) and the voltage is high enough, electricity can still "jump" through air - this is what an arc is.

The current rating is the current that the fuse can carry for indefinite time periods without opening.

In short, it's OK, you can use it as long as it fits