Ctrl + should work for the regular + key, not just the num pad one
At the moment (using Windows at least) the ctrl + zoom option only works for the num pad +; but it works for both the regular - and the num pad -. It would be helpful to have the regular + work for keyboard zoom too, especially for those of us who sometimes use a keyboard without a num pad area.
Comments
Consider the alternative Ctrl+mouse wheel
You can add the other option in Preferences, which is found under the Edit (or MuseScore) menu. Click the Shortcuts tab button and search for zoom.