The way to find the keys is as rewards for completing different activities in the game, especially in the first part of the game, you get them as rewards for completing domains. The Wolf Temple and the Lion Temple are places where you can get the first places in Mondstadt.
You can get the shrine keys as a reward when you complete quests in Mondstadt such as New Horizons of Adventure Archon Quest. And you will receive three for achieving adventure rank 25.
When you go down to Liyue, the method to have the keys continues the same pace, you will have to disappear domains like Forsaken Ruin and Wayward Path, and The Tree Who Stands Alone and The Chi of Guyun quests reward you with one each.
After presenting you with this guide on how to get shrine keys Genshin Impact, we hope that you can receive these keys as rewards in the game so that you can advance.