SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8e7a2d140e08c481e517810c83c0e9cad69c31989167af06b90a3bc68dd3f9d' 
  AND token = 'XzdXgENLwOHu56JZUOeO6QoquQtLXvs9YxIRyOZj7lM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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