Sandbox

SELECT 
  DISTINCT warehouse_id 
FROM 
  netting_store_locations AS sl 
  INNER JOIN netting_warehouses_products_amount AS wpa ON wpa.warehouse_id = sl.store_location_id 
WHERE 
  wpa.product_id IN (766)

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}