SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8ff5baa5a5f786797fe00d88a6b88f65218c3a25eea3b43f5677ff2a54b43f2' 
  AND token = 'u9xU0GYYxJFrKemJLjHwKqF3FTwBib+lYZ2wVTiVCvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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