A possible approach is to use whereRaw() method to build a raw WHERE clause for your query. The actual statement depends on the JSON structure and in your case you need two OPENJSON() calls to parse the nested JSON content:

->whereRaw(
   "EXISTS (
      SELECT 1 
      FROM OPENJSON(updated_value) j1 
      CROSS APPLY OPENJSON(j1.[value]) j2 
      WHERE JSON_VALUE(j2.[value], '$.phone_number') = ?
    )",
    ['5555555555']
)

As an additional note, if the JSON content has this fixed structure (two nested arrays, the first one containing a single JSON array and the second one with a single JSON object as item), you may simplify the statement:

->whereRaw(
   "JSON_VALUE(updated_value, '$[0][0].phone_number') = ?",
    ['5555555555']
)

You can use the JSON_VALUE function to extract the 'phone_number' value from the JSON data

$existing = DB::select(
    "SELECT TOP 1 * 
       FROM contact_change_logs 
      WHERE JSON_VALUE(updated_value, '$[0].phone_number') = '5555555555'"
);

You can use whereJsonContains() instead of where() .

$existing = ContactChangeLogs::latest()
        ->whereJsonContains('updated_value->phone_number', '5555555555')
        ->first();