If it is not indexed quickly, there is a queue with rather unpredictable waiting time. It can be days or weeks. It can also become "overlooked" or not indexed intentionally. Since no information is given, an observed "maximum" seems to be around 30 days. After that you might want to appeal or complain.
And should it be about a mature game, you have to be logged in and have mature content enabled to search and find it. (The game in question here is not marked as mature, but some of these indexing threads are about this issue).
Also the search features are being changed currently. So it might be, that you do not find your game, because it is not in the ~60 results that come up with your search term. Full titles work best for search, but some titles conist only of generic words. You can check the tag combinations of your game, if it is indexed. Like so https://itch.io/games/tag-3d/tag-atmospheric/tag-creepy/tag-dark/tag-first-perso...