Note: Holding down a key temporarily activates a tool. Letting go of the key returns to the previous tool.

Click the first point; Shift-click additional points: Select multiple points in Curves panel

Note: IF you prefer channel shortcuts starting with Alt/Option + 1 for red, choose Edit > Keyboard Shortcuts, and select Use Legacy Channel Shortcuts. Then restart Photoshop.

Note: If you prefer channel shortcuts starting with Ctrl/Command + 1 for red, choose Edit > Keyboard Shortcuts, and select Use Legacy Channel Shortcuts.