I suspect that KinoSearch would work about as well as a database like SQLite or PostgreSQL for this. It's actually a decent conceptual match -- inverted indexers like KinoSearch, Lucene, Xapian, etc. are optimized for many reads and fewer inserts, as opposed to the typical B-tree indexes on databases which handle inserts a little better. The only thing that's odd is that the original poster doesn't seem to need the relevance-based ranking that inverted indexes do well.

Regardless, the problem is straightforward and there are lots of good options for solving it.