The short answer to me is YES. When Google's Panda and Penguin algorithms rolled out, the reported sites that were hit had nothing but URLs that were specifically targeted at spammy keywords and keyword variations. I will worry if the keywords you are targeting have a lot of competition or high search volume.
Now, the most important thing to consider is the usability you are providing with your site structure considering your main goals or website purpose.
To me these two URLs belongs to two different websites
example.com/chrome/extensions-to-block-sites-in-chrome/
example.com/extensions/block-sites-in-chrome/
Does your site structure help the user take quick actions to find the information they are looking for?
Long URLs has also usability problems
Have you considered:
example.com/chrome/blocking-site-extentions
By looking just at either url I have doubts, What Kind of sites am I blocking? how about:
example.com/chrome/bad-site-block-extentions
See where I am going?
In general avoid thinking just in keywords, give preference to memorable shorts URLs, make it descriptive as possible and try to avoid "stop words".