Go to Menu bar search for Keyboard in your Ubuntu Mint.
Click on Shortcut Tab on Keyboard Dialog box.
On Custom Shortcut vertical tab create one Add Custom Shortcut.
Name: fake
Command: /bin/false
and in Keyboard bindings
assign CTRL+Q
Now you should have a new entry with your applied name and your keyboard setting. Every time you press Ctrl+Q your system will run the command /bin/false which basically does nothing. So this is a workaround to disable the setting.
