You don’t necessarily need the physical box to find your serial number. If your device is connected to your network, you can retrieve it through several online/software methods:
Hikvision's online verification is typically handled by regional branches rather than a single central site. How to Check / Find Device Serial Number : Hikvision Portal Hikvision Serial Number Check Online
Note: URLs may change. If a link is broken, search "Hikvision Online Warranty Inquiry" via Google to find the current official page. You don’t necessarily need the physical box to