I assume that you have one with the newer key style.
My Givi MAXIA 4 has this style. I just sent the code from the existing key to these guys and they sent me 2 keys that work perfectly.
https://www.replacementkeys.co.uk/vehicle/motorcycle/givi/However, since you are not in the UK you will need to search for "Givi SL key blank".
That should show you who supplies key blanks.