1. There is 2 possibility on your parcel:
Either it did not go through the Security check in Guangzhou or it did and the parcel is on it's way to your country Cambodia.

2. The parcel was mail by China Post Ordinary Small Packet Plus, this is the most economical way to send a parcel overseas. Usually it take 30 to 60 days to arrive in any country, because those type of parcel does not have priority to board aircraft departing China. Those type of parcel can only be track in China.

3. If your parcel did not pass the security check then the parcel did not depart China. You can have a look at this:
What does the status “Export Security Scan” mean? How long it will take?
On this site:

What does the status “Export Security Scan” mean? How long it will take?

4. You could contact seller and ask him if the parcel departed China because the tracking that you have does not mention that. He could contact China Post Hot Line: 11185 to find out what happen to the parcel.

5. Just make sure that you still have buyer protection for the parcel in case you have to open a dispute.

Hope this help.