The crucial point for that decision is how legitimate the journal is (or tries to be) and how much on the untrustworthy side where they try to make money any way they can it is.
If they try hard to appear trustworthy or they are honestly trying to set up a journal but are really bad at it, unsubscribing may well work and not have negative repercussions - obviously you are not the guy to fall for them and they might move on to other candidates. However, if they fall into the "general villain" category - making money any (illegitimate) way they can - then trying to unsubscribe might well not work or have other negative side effect. That could be you receiving more spam or being targeted for more elaborate phishing attempts as you have proven that the mail address is actively read by someone. No one can tell you for sure what will happen either way in general. It's always a probability game.
However, as mmeent points out: As always it is prudent to not just click on any link in a mail. Instead check where the link points, go to the main website and see if that is a website affiliated with that journal/publisher or a generic mailing list provider. If it is the first, just look on the website for an unsubscribe option or hand-type the url from the mail if you want to try to unsubscribe.
If it is the latter, the same analysis that you just did for the publisher applies to the mailing list provider - is it legitimate or not. If you still want to unsubscribe look at their page for such an option or again make sure you actually end up on an address on their page when copying the link.
If there is a 3rd party mailing list provider involved that is legitimate and you consider the publisher so far in the villain area that you consider them criminal, reporting them to the mailing list provider might also be a way to shut their mails down...