SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ba36e2e9522557aa3fc222a99258539113a4133af75b546de83b11e7a37b212' 
  AND token = 'XjVGKrYVw6jtZubZ600fYJC+tdGMtHvsAAOFoYXkr2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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