SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fb9e2e28a16c5c657d8a10cdc1f07d0257b9ac7265a223bd8d86408b21bed0cf' 
  AND token = 'E8+2B66ULyKsgbIn3AG6PDiBFVgGLXgaj/+u7qqisaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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