If you want to disable the single-click editing workflow, you can turn off the Left-dragging moves selected keys preference in the Animation (Settings) preferences and use the Move Nearest Picked Key Tool on the Graph Editor toolbar to explicitly move keys with the middle mouse button. (Disable Left-dragging moves selected keys in the Graph Editor heading in the Animation preferences.)
Select Edit > Transformation Tools > Move Keys Tool > to open the Move Key Settings:
Move Only
disables the tool's ability to sweep throughout a curve's keys (see Move Over).Move Over
(default) lets the tool sweep through an active curve along the curve's keys. This expedites the fine-tuning of animation curves.Constant
moves all keys the same amount in the direction you drag.Linear
moves all keys based on the distance they are from the mouse down location. The amount a key moves decreases linearly as its distance from the mouse down location increases.Exponential
moves all keys based on the distance-squared they are from the mouse down location. The amount a key moves decreases exponentially as its distance from the mouse down location increases.