After looking up the journal name (Journal for Internet Technology and Secured Transaction (JITST)), I discovered this journal was not listed in either the SCI or EI indexes. Is this journal worth publishing in? More generally, how do I judge journals that are not indexed?
There are good journals that are not listed in the SCI, so this alone does not mean that the journal is bad. However, an overly long list of topics including non-descript terms like "web-service" and "Future technologies" looks bad. Also the sentence "Our journals’ impact factors have been compiled by Indexing Citation Board (ICB)." is pretty suspicious, when you find out that ICB is actually "Infonomics Society’s Indexing Citation Board (ICB).". A review process of 4 to 6 weeks is also not hinting at serious checking. So even if this is a serious journal, someone tried really hard to make it look like trash, and I would definitely not consider publishing there.
It really depends on your field to determine if it is worth publishing in or not. Some reputable, but niche, journals don't get indexed very broadly but are well respected and read by members of that discipline. As such, your best bet is to see if you recognize any of the names of peers in that journal and then publish accordingly. You might also want to reach out to some of them directly to see what their experience was as well. It should be noted that that generally journals will work to get themselves added to major indices so an old (i.e. more than twenty years) that isn't indexed may be a red flag.
On the subject of red flags, you may have noted the copyediting that went on with your post. Another thing to be careful of is similarly named journals as is the case of the International Journal of Internet Technology and Secured Transactions (IJITST) and the Journal of Internet Technology and Secured Transaction (JITST). There is a subtle difference there if you are just looking at the acronym and personally it raises a red flag for something worthy of close inspection. If you look the journals and publishers up on Beall’s List of Predatory Publishers, you will find that the publisher for JITST, Infonomics Society, is there. Inderscience Publishes, which publishes the IJITST, does not appear to be listed.