SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a417ad2da952420a0898e4158f359bbb6560d4510e414cc233856cf6cf7b9ac2' 
  AND token = '4QXrtBkGNq4hGW3kUz5Zy8LK1QFrguPAWuTGJS4FZv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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