Short answer: Yes.
Unlike Google and Bing, Yandex does make use of the meta keyword tag, and in their official documentation describes the tag (and its contents) as:
It can be used when determining the page’s relevance to search queries.
Optimizing Meta Keywords For Yandex
Optimizing your meta keyword tag isn’t too dissimilar from other forms of keyword optimization.
Whilst they do play a part in Yandex’s algorithm, they’re only a small part of it – and you still need to apply a logical test to the page and its content, that being if you take away any form of meta keyword, does the page lose meaning? A form of page regression was you take away various elements one by one, and ascertain if they page and it’s desired content can still be understood.
Meta keywords should be highly focused for the page, be concise and representative of the page content. So, for example, a page selling tomatoes could contain the meta keywords:
<meta name="keywords" content="помидор, помидоры, свежие помидоры, помидоры сливы" />
But over-optimization of this could look like:
<meta name="keywords" content="помидор, помидоры, свежие помидоры,купить помидоры, продуктовый магазин" />
With any form of page element optimization, you should look to use variants of the target search phrase across the title tag, page H1, page subheaders, and meta keywords without turning content into something mechanical and not user-friendly.