Since when did control change messages have velocity? I think you mean "value".
The typical way to do what you suggest is for all values below 64 to clear the LED, and all values 64 and above to set it. Although usually buttons send 0 and 127 as the values, programming this way allows your code to work with non-standard things that send something else.
If I were you, I'd have a good hunt around on Google. Handling simple MIDI control changes using Arduino must have been done a dozen times, and someone is bound to have put some code online somewhere.
HTH,
Tom