First, there is no such thing as anonymity. The more information you divulge in a review the easier it is to identify the exact person who posted it.
Second, you have to weigh the consequences of your speech. Sure, you can write whatever you want in a review but there may be negative consequences for doing so. Obviously you are now running into some of those consequences. I'm not going to tell you to change or remove your review as that's a personal decision. Rather I'm just going to say that you should think about this before posting too much information if you decide to do it again in the future.
You've now burned a bridge. Although you need to list that employment on your resume, I wouldn't try to use them as a reference. Depending on what country you are in that employer may not even be contacted with regards to your work history. And even if they are, hopefully only HR will be contacted and not the owner that way this specific problem is "forgotten" about.
Which leads to the next thing - it's incredibly unlikely that a future employer will question you about things that pop up during their due diligence on you. Which means it's unlikely you'll have an opportunity to explain yourself.
My advice is simply to not worry about it until it comes up. If it does then honestly answer their questions.