Formatting library row based on dates, but ignoring blanks

I'm trying to use the in-built tools to format a row in SharePoint online.

It is simple, I want it to highlight the row red when the due date is in the past AND another column value has been set. I use the row formatting to achieve this, but it still picks up blank dates and highlights them red.

How can I get it to ignore empty dates?

Here is the code being used:

{
  "$schema": https://developer.microsoft.com/json-schemas/sp/v2/row-formatting.schema.json,
  "additionalRowClass": {
    "operator": ":",
    "operands": [
      {
        "operator": "&&",
        "operands": [
          {
            "operator": "<",
            "operands": [
              {
                "operator": "Date()",
                "operands": [
                  {
                    "operator": "toDateString()",
                    "operands": [
                      {
                        "operator": "Date()",
                        "operands": [
                          "[$Expires]"
                        ]
                      }
                    ]
                  }
                ]
              },
              {
                "operator": "Date()",
                "operands": [
                  {
                    "operator": "toDateString()",
                    "operands": [
                      {
                        "operator": "Date()",
                        "operands": [
                          "@now"
                        ]
                      }
                    ]
                  }
                ]
              }
            ]
          },
          {
            "operator": "==",
            "operands": [
              "[$ExpiredDocumentUpdated]",
              "No"
            ]
          }
        ]
      },
      "sp-css-backgroundColor-BgDustRose sp-css-color-DustRoseFont",
      ""
    ]
  }
}