Decrease No.of days by 1 daily from MySQL Column

I want to decrease the number of days by 1 daily. And update the remaining days in the same row and column. Below you can see my MySQL table :

In the above image, you can see that I have a column "licence_validity" that contains the number of days and you can also see I have another column "activated_on" now this column will be filled when licence get activated with the current date. Now I want to decrease the number of days by 1 daily in the licence_validity column when activated_on column has a date.

Now I want to decrease the number of days by 1 daily in the licence_validity column when activated_on column has a date.

I am understanding this correctly, that's a simple update:

update users
set license_validity = license_validity - 1
where activated_on is not null

If you want to do this on a daily basis, then you might want to use the event scheduler. Something like:

create event event_update_users
on schedule every 1 day
do
    update users
    set license_validity = license_validity - 1
    where activated_on is not null;