SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (595, 594)

Query time 0.00025

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": 2,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (595,594)"
    }
  }
}

Result

product_id product_code product_type status company_id list_price amount weight length width height shipping_freight low_avail_limit timestamp updated_timestamp usergroup_ids is_edp edp_shipping unlimited_download tracking free_shipping zero_price_action is_pbp is_op is_oper is_returnable return_period avail_since out_of_stock_actions localization min_qty max_qty qty_step list_qty_count tax_ids age_verification age_limit options_type exceptions_type details_layout shipping_params facebook_obj_type parent_product_id __variation_code __variation_options __is_default_variation
594 PSA9 P A 1 9720.00 3 0.000 0 0 0 0.00 0 1513866455 1560996571 0 N N N B N R Y N N Y 10 0 B 0 0 0 0 7,8 N 0 P F default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} activity 0 N
595 LSA9 P A 1 9720.00 4 0.000 0 0 0 0.00 0 1513868873 1560996571 0 N N N B N R Y N N Y 10 1518015600 B 0 0 0 0 7,8 N 0 P F default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} activity 0 N