I thought that the question with an upvoted answer cannot be auto-deleted. (And that it can be deleted only by votes of users who have privilege to vote for deletion.)
In faq entry How does deleting work? What can cause a post to be deleted, and what does that actually mean? What are the criteria for deletion? it says about the deletion by the system:
By the system:
The system will automatically delete closed (not as a duplicate), unlocked questions with zero or negative score having no upvoted or accepted answers or pending reopen votes, that were closed 9 or more days ago and haven't been edited in the past 9 days.
The system will automatically delete unlocked, unanswered questions that have negative score after 30 days.
The system will automatically delete unlocked, unanswered questions with score of zero (or one if the owner is deleted), fewer than 1.5 views per day on average, and fewer than two comments after 365 days.
The system will automatically delete any question (and its answers) or answer with a score less than 0 when its owner's account is deleted.
The system will automatically delete questions migrated to other sites after 30 days.
If I did not miss something, the only case is if the owner's account is deleted and score is less than zero (the fifth point). This happened, for example, here.
However, this question was autodeleted, the user still exists and it has one upvoted answer. It was closed but if I understand correctly the second point (which mentions deleting questions having no upvoted or accepted answers or pending reopen votes), if there is upvoted answer, it should not be deleted.
Screenshot showing the state of that particular question at the moment: