Hi,
Thanks for the post,
Unfortunately, it is not possible to restorer the database without the encryption key. The encryption key(pmp_key.key) is unique for each and every installation and the values stored in the database will be encrypted based on the key. Even, the database backup files are stored in encrypted zip format. So, there is no way restore the database without encryption key.
By, default the encryption key(pmp_key.key) will be present <PMP-Home>/conf folder. You can edit the file named manage_key.conf present in <PMP-Home>/conf folder to look for the encryption key location and change the location of the key by editing the same file. More information on managing the encryption key is available in this link.
Feel free to write us if you have any other questions.