The directory is usually inside your home like this:
logins.json contains the locations, username and password
key*.db (usually then name could be key3.db or key4.db)
Without the key file you will not see any passwords in Firefox as it is required to in order to decrypt the contents of logins.json
Copy those files and restore them to the current machine/profile and you should be able to access your old passwords.
Just copy and restore