SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffb471ba810f1c8a905aa6e978da8294154dc1d1881fc004e82a3e3e21bee2a0' 
  AND token = 'FWyFSrUYkoH9hIgsvbmxyE79htOtX+0XmZrDwR3GDpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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