MySQL offers this via use/force index (…). Similar problem where the QP will inexplicably decide one day to make a query really slow and you gotta override it.
We have a couple queries where using the correct index they'll take milliseconds, using the wrong index it'll take minutes - and mysql occasionally enough to be a noticeable load on the database chooses the wrong one and we've specified "USE INDEX" even though I really hate having to do so.