Sandbox

SELECT 
  warehouse_id, 
  amount, 
  store_type, 
  position, 
  main_destination_id, 
  pickup_destinations_ids, 
  shipping_destinations_ids, 
  status 
FROM 
  cscart_store_locations AS sl 
  INNER JOIN cscart_warehouses_products_amount AS wpa ON wpa.warehouse_id = sl.store_location_id 
WHERE 
  wpa.product_id = 276703 
ORDER BY 
  sl.position ASC

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}