The canonical answer on reviewing in the LQP queue is here: What are the guidelines for reviewing?, although it doesn't directly address the situation in this question.
Both questions and answers can end up in the LQP review queue.
Questions
Questions and their downvotes are visible on the main page, so spam questions are usually removed pretty quickly. Sometimes the spammers are clever, and people don't catch it. So you can occasionally run into spam questions, that were not previously flagged, in the review queues. By that time, the question may no longer be visible on the main page.
Open questions can't go directly to deletion by voting in a review queue. The voting option in the LQP queue is closure. So if you come across "real" spam, you can both flag it as spam and vote to close (or "recommend closure" under 3K rep).
Closure doesn't affect the spam bots. Spam questions may be bait for spam answers, or may attract answers from unwitting posters. Spam usually gets deleted before there are enough closure votes, but it's still another path to get it out of circulation if flagging is slow.
But close votes also provide another benefit, they provide an indicator on the question, visible to 3K+ users, and may get the question on the Moderation Tools tabs, visible to 10K+ users. Those indicators can alert additional users to problem posts to speed getting more eyes on the post for action.
The Close option is also an acceptable response in the review queue after you flag it. I don't recall ever seeing an LQP audit that used a real spam question (those tend to be in the First Posts review queue). But I think I've seen some legitimate questions with the "Review this carefully, it might be spam" warning as an audit. So spam questions shouldn't be an audit problem in the LQP queue.
Answers
There are no flagging options in the LQP queue, so if you find what you think is a spam answer, you have to go to the post to flag it. And, of course, there you can see whether it's an audit.
If it's not an audit, flag it as spam. That gets it into the "spam handling system". You can also leave a comment to alert other readers if it isn't obvious spam (some spam is obvious at a glance, and some is recognizable only if you read through it and maybe do some additional checking). A comment will help other readers recognize it who might not otherwise take the time to dig into it. But, of course, only leave a comment if you are sure it's spam.
Back on the review page, you don't want to select the Delete or Edit option because we need to educate the spam bot.
"Looks OK" might seem like an OK option (you've already done everything you can do, what difference does it make in the review queue?). Here's the problem. There are a limited number of places where answers get exposed to flagging by alert readers. On the main page, everything is posted under the question, so answer content and downvotes aren't visible, and can't alert readers to spam. It is seen by the readers who happen to view the answer, potentially by 10K+ users who happen to see it in the Moderation Tools, potentially or eventually by moderators, but mainly by people in the review queues (that's where the spam flag sends it). A few "Looks OK" clicks takes the post out of the review queue.
So the only real option is to click Skip.
If it is an audit, and it was really a spam answer, it's already gone. The audit system is just to make sure that you're awake and paying attention, it isn't really about being right (there are endless cases of bad audit examples and logic). If you recognize that it's an audit, just play along with the game (passing means you're paying attention). The "correct" response to spam (even though it's the wrong real response), is to click on Delete. You can't win this one. If you click Skip on general principles, you will remain "due for an audit", so you will continue to get audits until you deal with one (probably not the next review post, but soon).
