SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bb2fdad6791d03951964533f0b16c21da7fcfc36bd7cf8215835dfff0205f28' 
  AND token = 'jytQ9IHBnWuRqX/ELUiYWSZw2Q8UvpGiPBy098mvWTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}