So, I would assume that when you mention you have one keyword “it is the only one”, in that case, it could be that the ad is being shown on 2nd page or 3rd, and not on the first top, due to which you’re getting more impressions and fewer clicks, you can try putting placement or increasing bid, this way you’ll be able to increase clicks, however, if this is not the case and you have lower CTR, you all of your keywords or campaigns for that matter, you may have to re-work on your images, promotions, coupon, etc. can also help with the CTR.
