On VSCode, how to open the selected folder from Explorer view into the current open terminal (without opening a new one)?

1. Install the multi-command extension

This allows us to create a sequence of commands that can be used by a keybinding.

2. Add this snippet to your settings.json

"multiCommand.commands": {
  "multiCommand.openFolderInTerminal": {
    "interval": 10,
    "label": "Open Explorer view folder in active terminal",
    "sequence": [
      "copyFilePath",
      "terminal.focus",
      {
        "command": "workbench.action.terminal.sendSequence",
        "args": { "text": "cd \"" }
      },
      "workbench.action.terminal.paste",
      {
        "command": "workbench.action.terminal.sendSequence",
        "args": { "text": "\"" }
      },
      {
        "command": "workbench.action.terminal.sendSequence",
        "args": {
          "text": "\u000D"
        }
      }
    ]
  }
}

What this effectively does is to copy the path of the selected folder and send sequences of text to the terminal, as stated here. The quotes are escaped by \ and Enter is sent by the newline unicode character \u000D.

3. Add a keybinding to your keybindings.json

{
  "command": "multiCommand.openFolderInTerminal",
  "key": "ctrl+enter",
  "when": "filesExplorerFocus && !inputFocus"
}

The value of the "command" key has the same text as the one defined on the "multiCommand.commands" object.