When submitting a paper, should I match the keywords to MeSH terms?
Keywords were supposed to be, considerably, fixed based on Medical System Headings (MeSH), when the aforementioned web-based searching systems were not still at the service.

Nowadays, the researchers often try to take scrutinized search into account to acquire their target papers and resources, as close as possible to their contextual subject. If you are doing a specific regime of research, do consider the to-the-aim keywords, specialized for your work. Because they will be traced by the search engines, efficiently.