An alternative that might work is jupyter.runcurrentcell. For example:

{
  "key": "cmd+enter",
  "command": "jupyter.runcurrentcell",
  "when": "editorTextFocus && isWorkspaceTrusted && jupyter.hascodecells && !editorHasSelection && !isCompositeNotebook && !notebookEditorFocused"
}

@aaron approach did not work for me.