Let's take a little bit deeper look into this. You have optimized well and you have done so for some pretty good keywords! So you are on the right track... but you still failed to rank for what appeared to be some good terms. That is unfortunate, but it will happen and it is important to note that you had the right approach. That approach simply failed to deliver, and there are some actionable items that you can address in the future to fix this issue.
First, let's take a look at the top-5 videos ranking for that search term:
The wonderful thing about the YouTube Search and Discovery systems is that they want to push new content for people who are searching for it. We all want the fresh new thing and YouTube is no different. Looking at this list you have a good opportunity for exposure because four of the top five videos are 8 months or older. That will give you a foot in the door for the first few days after you publish your video. YouTube will test your video out against select audiences to see if you are going to perform as well as these guys. But that opportunity is limited. You have to outperform these guys. And as you can see you are up against videos with 15k, 1.2MM, 10K, 508K and 311K views. Not only are you going up against some stacked competition but these videos are at least twice as long as yours.
YouTube values watch time. It is their number one metric... they want eyes on platform for as long as possible. Every one of these videos is at least twice as long as yours. That doesn't mean you can't compete; you can. If your video causes viewers to share it out, rewatch it multiple times over and watch like fifteen other videos after this one then this thing is a winner. But understand that the watch time your 2+ minute video earns is up against the watch time earned by 4, 5 and 13 minute videos.
I DO NOT encourage you to jump in and start making 30 minute videos... that is not the answer. We are talking about
watch time and not
run time and there is a difference. But be aware of what you are competing against.
I would mention too that when we are talking about being aware of your competition, there is a glaring omission in this list of top videos. The thumbnails are all... well kinda bleh. Not one of these really stands out. If your thumbnail was bright and flashy and it would totally stand out against these guys. That is something you should consider before you post; take advantage circumstances like this. The thumbnails in this search are poor and that is an opportunity for you to get your foot in the door.
But the keyword was Excellent?
I know, we all feel that way sometimes. It is an excellent keyword that you selected. Despite that you failed to beat the competition. But there is a silver lining here. You did it right, you scored an impressive amount of views despite only 3 subscribers, you can always get a random boost again in the future and I think that honestly... you only need to build a little more authority in the algorithm to compete.
Even though this is Excellent, you are still competing with the top end of 178,000 other videos. That's not terrible, but obviously your channel is just not yet big enough to compete with that level. So my advice; first aim for keywords with a little less competition. Not much; you are closer to competing for this than you think. But go lower until you start to establish yourself in the ranks for these keywords and then work your way back up. Second; be mindful of your competition, particularly Thumbnail omissions like the one I mentioned earlier. That is a critical opportunity, and one that could very likely have landed you much higher in the ranks. You obviously performed for these terms, it just didn't last and I guarantee I high CTR will end up holding rank on it's own merit. In fact I would encourage you to try to do another video with this series of keywords with the following changes; make it 4:59 long and give it a bright red thumbnail. See what happens then.