How to enhance my use of Google Scholar?
No, you cannot follow specific papers or journal-level keywords on Google Scholar; you can only follow researcher profiles.
However, there are other databases that support such a functionality.
Alert for specific keyword-searches in journals
For instance, on Web of Science, you can set an e-mail alert for your search keywords. Using their Advanced Search Options, you can design your keywords such that you only search in specific journals and only in their Abstracts and Titles. After you have done your search, click on Create an alert in the left menu.

The same applies to Scopus where the option is named Set alert:

Alert for specific papers
On Web of Science, click on a search result or publication. On the right-hand side, under the heading 'Citation Network' you can click on Create Citation Alert:

In Scopus, the same function can be found as Set citation alert.

Or on ResearchGate, you can get alerts for citations to specific papers by clicking Follow: