SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b548f917a96bcef57b3e12a11a69b938edcdb2a4f96a3d252023496e7785deb' 
  AND token = '6zpdqPG8SiKuLw6+IhT/ljYmKExG8W96yETQH9V2XYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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