All shortcuts in GIMP are easily customizable. The existing, defaut, shortcuts are visible on the right side of each menu entry. To create others, you just go to
edit->preferences->interface->shortcuts - which personally I don't like, as it takes too long to set up each wanted shortcut. The other way is to go to
Edit->Preferences->Interface and enable the
Use Dynamic Keyboard Shortcuts option.
From there on, just highlight any meny option, by hovering the pointer to it, and press the desired shrotcut for that option (For example
a, or the any number from
9). That is it - the shortcut is configured.