SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f86097098992ed17c555303c6f5d0f33828288a5b5dcf3ec9d20a36e4930655' 
  AND token = 'eE6+wTKhwIYFjpZR720ZgpDq8usIj1LiAQr4xUD/VvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}