Even though Command-K is one shortcut to access many things quickly, there are also direct shortcuts to trigger popular actions.
A cheat sheet of all available shortcuts can be found with  ⌘/Ctrl    K  and select Keyboard shortcuts.
 Make sure you’re outside the composer before using these shortcuts.
Main shortcuts
 [  Show or hide the left menu.
 ]  Show or hide the right menu.
⌘/Ctrl   H  Hide or show conversation events.
Conversation shortcuts
 ⌘/Ctrl   Shift   Y  Close a conversation.
 ⌘/Ctrl   Shift   O   Reopen a conversation.
 Z    Snooze a conversation 
 P  Change the priority of a conversation.
 A  Assign a conversation to a teammate or inbox.
 Composer shortcuts
 R  To compose a reply.
 ⌘/Ctrl   Enter  Send the reply.
 ⌘/Ctrl   Shift    Enter Send the reply and close the conversation.
 ⌘/Ctrl   Option    Enter  Send the reply and snooze the conversation.