Does dark one's own luck just apply to the next ability check?

[Nox Ffred Dragon]

"At level six, Fiend Warlocks gain the ability "Dark One's Own Luck," allowing them to add 1d10 to an ability check once per short rest."

I tried flipping the toggle and didn't get any further options so my guess is it just applies to whatever the next ability check happens to be but wanted to confirm?

Thanks!

[Tax evasion]

If it is an ability check, it might be a bonus just like guidance if it is an active check, and bardic inspiration if it's passive.
Meaning that, if it's a passive check, it will add 1d10 if you have a chance to succeed it with it (if you roll a 5 and you need a 17, it won't be added, but it will if the target is 10)