SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2358a46200250df1b6394d1dec1f711b4955baa1cac319d495745f9fea152003' 
  AND token = 'uFMI+Pow2NDWpXUymlzStacx8Hzq3gAPFwlVU7KcKwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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