Is there a keyboard shortcut to select current word?

If you have CamelHumps enabled, Alt + J will be your friend.

Yes there is but it's different from one IDE to another, And here are 3 examples:

• SublimeText: Selection -> Expand Selection to Word (The shortcut will be shown next to it according to your OS)
• PhpStorm: Edit -> Extend Selection (The shortcut will be shown next to it according to your OS)
  • MAC Extended Selection Shortcut: ⌥ + ↑
  • MAC Shrink Selection Shortcut: ⌥ + ↓
    
  • MAC Select all occurrences: ˄ + Command + G
• Visual Studio Code: Selection -> Add Next Occurrence (The shortcut will be shown next to it according to your OS)
  • MAC Add Next Occurrence: Command + D
  • MAC Select All Occurrences: Shift + Command + L

^+G it should work across all JetBrains IDEs

Ctrl + W selects the current word.