By default, hactool (and many tools based on it) looks for the keys file in your . It does not look in the same folder as the hactool.exe file (unless you tell it to).
Hactool is a command-line tool developed for Switch enthusiasts and developers to manipulate game data, including encryption and decryption. Prodkeys, short for "product keys," are files used to decrypt game data, allowing users to play games on their Switch consoles. These files are usually extracted from the Switch console or obtained from game cartridges. hactool prodkeys does not exist fixed
This manually tells hactool: "Use this specific key file right here." By default, hactool (and many tools based on