Why is possible_keys NULL when they are in the right order?

Question

MySQL

Here is the request:

EXPLAIN select SQL_NO_CACHE `id`, `title`, `alias`, `content`, `published_at`, `image`, `thumb`, `parent_folder_id` from `slc_articles` order by `sticked` desc, `published_at` desc limit 21

Indexes:
But it does not use them:

Perhaps because I put a 1-in composite index on everything, perhaps if I make several different ones for each query, will the muscle automatically select the desired index?
Why?

Answer 1

MySQL can only use an index if the fetch or sort starts on the first column of the index. Your query must have an index whose first column is `sticked`.