I am writing a computer science paper that has a keywords section that comes directly after the abstract. Currently I have just one keyword in there, how important is that section? Do I have to come up with as many related keywords as I think of, or nobody actually uses this section and I can ignore it?
A recent statistical analysis finds that the number of keywords has a small and significant effect on how often a paper is cited. This suggests that adding some keywords to your paper is good for you and for those would try to locate and cite relevant literature. Thus, you should not ignore the keywords but enter as many relevant keywords as the journal's house style allows.
Shahadat Uddin, Arif Khan, The impact of author-selected keywords on citation counts, in Journal of Informetrics, Volume 10, Issue 4, 2016, pp 1166-1177.
The number of keywords you should use depends on the journal you will submit your paper to. They usually require 3 to 5 keywords so they can direct the paper to relevant reviewers and editor.
It also makes it easier to get recognition since search engines utilizes keywords instead of scanning whole papers.
In short: No, you definitely should not ignore it. You should write down related keywords but do not exceed the number of journal.
Additionally each journal has a "Author's Guideline" documentation. If a submission fails to meet these guidelines, your paper is most likely to be rejected even before evaluation.