Filter models with pivot table extra field value in laravel

i have three table

tours (id , body) -> assume a record is (id: 1, body: somethings)

metas (id , key)-> assume a record is (id: 1, key: tour_price)

metables (meta_id , metable_id, metable_type, value) -> assume a record is: (meta_id: 1, metable_id: 1 , metable_type: App\Tour , value : 250000)

i want filter results with meta value like this :

where tour_price is 250000 ?

also my Tour model has function like this :

public function metas()
{
    return $this->morphToMany('App\Meta', 'metable')->withPivot('value');
}

i tried this :

        $tours = Tour::whereHas('metas', function($q){
        $q->where('key','tour_price');
        })->get()

it just return tours with tour_price key in pivot table. i want something like this :

     $tours = Tour::whereHas('metas', function($q){
    $q->where('key.tour_price','250000');
    })->get()

but it did not work .

via Chebli Mohamed