SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1607, 1608, 1606, 1703, 1578, 1396, 1605, 
    1206, 1586, 1934, 1932, 1933
  )

Query time 0.00084

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": 12,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (1607,1608,1606,1703,1578,1396,1605,1206,1586,1934,1932,1933)"
    }
  }
}