Angular 5: Access a non-global service from a route guard

Question

In my app I have a parent route with a series of child routes:

{
  path: 'parent',
  component: ParentComponent,
  children: [
    { path: 'child1', component: Child1 },
    { path: 'child2', component: Child2 }
  ]
}

I have a non-global service (MyService) setup as a provider in the ParentComponent, which is injected into both of the child components.

Now I want to add a route guard to the second child component, making the route definition like this:

{
  path: 'parent',
  component: ParentComponent,
  children: [
    { path: 'child1', component: Child1 },
    { path: 'child2', component: Child2, canActivate: [MyGuard] }
  ]
}

How can I access MyService from within MyGuard? If I try to inject it in normally, I get the no provider for MyService error.

I see the canActivate route guard can accept an route: ActivatedRouteSnapshot parameter, and this parameter has a component property. However, this property isn't an instance of the component, it just seems to be the class definition for the component. Am I supposed to create an instance of the component myself?

How can I get access to the service I require?