Two ways to enqueue an asset on an admin sub-page when it has been translated.

enqueue-asset-on-translated-admin-page.php

/**
 * Use the `$admin_page_hook[ $page_slug ]` in the `load-{page}` hook
 */
global $admin_page_hooks;
if ( !empty( $admin_page_hooks['myplugin-parent'] ) ) {
	add_action( 'load-' . $admin_page_hooks['myplugin-parent'] . '_page_myplugin-subpage', 'enqueue_myplugin_assets' );
}

/**
 * Or add `$admin_page_hook[ $page_slug ]` when checking the current
 * screen.
 */
add_action( 'admin_enqueue_scripts', 'enqueue_myplugin_assets' );
function enqueue_myplugin_assets() {

	global $admin_page_hooks;
	$screen = get_current_screen();
	if ( !empty( $screen ) && !empty( $admin_page_hooks['myplugin-parent'] ) && $screen->base == $admin_page_hooks['myplugin-parent'] . '_page_myplugin-subpage' ) {
		// enqueue your assets
	}
}