To visualize and manipulate the transform constraint keys for your animation, you should ensure that the dopesheet is properly filtered to show constraint keys. In the dopesheet, you can filter to show only the keys for constraints, which will help you see and adjust the timing of the mix values. If you can't see the keys, make sure that the dopesheet filter is not hiding them. You can also use the graph view to adjust the timing and values of these keys, but ensure that the sync option is not limiting the visibility of the keys you want to adjust.
To delete the red/green keys you see in the tree view, you can select them in the dopesheet or graph view and press the delete key. If they are not visible, ensure that the visibility dot for the transform constraint is enabled in the tree view, which will allow you to see and manage these keys more effectively.