How can I remove arbitrary keys when creating a type from an existing type in Typescript?

Question

Let's say I have a type defined as:

type ExistingType = {
  [key: string]: any;
  name: string;
  mobile?: string;
}

Now I want to create a type from this without the arbitrary keys like this:

type DerivedType = {
  name: string;
  mobile?: string;
}

Does there exist a less manual way of doing this without picking up the keys using Pick utility type?

I used Pick utility type to achieve this in the following way:

type DerivedType = Pick<ExistingType, 'name' | 'mobile'>

It works but it is very verbose, and if there are many keys in the original type then it becomes very tedious and unclean.