mysql – How bad is to have 3 unique constraints in a table?

I have a table with articles. In this table I have article_title (varchar 500), article_meta_description (varchar 2000) and article_content (longtext). All of them are set to be unique (each of them, not together).

Why:

article_title because it’s better for SEO

article_meta_description because it’s better for SEO

article_content because I want to be sure there won’t be unwanted duplicates made by a bad insert

I am aware that it may have an impact on insert performance, but I’m not sure about the size of impact. I also don’t remember to have seen 3 unique columns in a single table somewhere.

So, how bad is what I’m doing ?