SELECT 
  product_id, 
  is_stock_split_by_warehouses 
FROM 
  cscart_products 
WHERE 
  product_id IN (
    127, 128, 132, 134, 135, 137, 200, 201, 
    202, 203, 204, 219, 220, 221, 222, 223, 
    256, 257, 260, 261, 262, 263, 264, 283, 
    284, 285, 286
  )

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 27,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (127,128,132,134,135,137,200,201,202,203,204,219,220,221,222,223,256,257,260,261,262,263,264,283,284,285,286)"
    }
  }
}