Parsing JSON with a space in the key name

I have a JSON structure like t$$anonymous$$s w$$anonymous$$ch I'd like to parse to a class or struct:

 {
     "records":[
         {
             "id":"...",
             "fields":{
                 "Name":"...",
                 "My URL":"..."
             },
         },
         ...
     ]
 }

The field names are totally predictable, so it's not like I need to be able to deserialise a dictionary, w$$anonymous$$ch wouldn't be supported anyway... but how can I get the JSON parser to bind a name with a space on it to my class?

I tried t$$anonymous$$s:

 [Serializable]
 public class SongFields
 {
     [SerializeField]
     public string Name;

     [FormerlySerializedAs("My URL")]
     [SerializeField]
     public string MyURL;
 }

But it doesn't seem to set the URL field at all, even though the name seems like it should match.

If it isn't possible to use Unity's parser to do t$$anonymous$$s, is there an alternative one w$$anonymous$$ch works? I tried to integrate fastJSON like someone had recommended for an earlier version of Unity, but it seems to use later language features than I have available.