Select all Keys on Curve like in Maya

selectKeys $[3][1].track --select all position controller keys
--or you can use this but it's the same
selectKeys $.pos.controller
--For rotation and scale track keys use:
selectKeys $[3][2].track --rotation keys
--or
selectKeys $.rotation.controller
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selectKeys $[3][3].track --scale keys
--or
selectKeys $.scale.controller
--You can also specify the interval or time.
--This is the text from maxscript help:
--selectKeys <controller> [ <interval> | <time> ]
--Selects the specified keys in the track view. If an interval 
--is given, all the keys within the interval are selected. 
--If a single time is given, the key at that time is selected. 
--If no time or interval is given, select all keys.
selectKeys $[3][1].track (interval 0f 30f) -- select all keys in --interval from 0 to 30 frames
selectKeys $[3][1].track 29f -- select single key at 29 frame
--For more info read the topic in "Controller Key Functions" --maxscript help