How serious can this review invitation be?
Don't waste your time with it. You were smart to catch how the mail might have been generated (keywords etc). These mails are often sent out by journals that turn out to be predatory*; you wouldn't like to be associated with it.

If you accept, you may find your name being used here and there, in an attempt to increase the journal's scientific credibility. It is likely that their editorial board etc. is fluffed up in this manner (you could take a look at that if they've put up one, and see if there are any known researchers on their board). You are right — this is likely to happen repeatedly; ignore any requests that:


mention a specific paper of yours and extend editorial board invitations — it's a sign of auto-generated content.
appear in predatory journal lists.
have extremely general scope (eg. STEM) and no matching editorial board.




EDITS: 
(1)* Predatory journals,  in a nutshell, charge authors exorbitant fees to publish articles with little or no peer review, with very low visibility or scientific credibility. In the most extreme cases, the article may not even be published. In this manner, they are 'preying' on unsuspecting authors who submit their hard work. The linked question contains a detailed description.

(2) It would be a good idea not to respond to such mails at all, and to mark them as spam. Over time, it ll get easier to spot them right away.