SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (3478, 370, 85)

Query time 0.00040

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": 3,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (3478,370,85)"
    }
  }
}

Result

product_id product_code product_type status list_price amount weight length width height shipping_freight low_avail_limit timestamp is_edp edp_shipping unlimited_download tracking free_shipping zero_price_action is_pbp is_op is_oper company_id is_returnable return_period avail_since localization min_qty max_qty qty_step list_qty_count tax_ids age_verification age_limit usergroup_ids options_type exceptions_type details_layout shipping_params out_of_stock_actions updated_timestamp facebook_obj_type parent_product_id cp_bar cp_seo_use_addon cp_seo_no_index cp_sr_variation_type cp_fake_product cp_not_crop_auto
85 F-SB A 6.49 100 4.500 0 0 0 0.00 0 1244437200 N N N D N R N N N 1 Y 10 0 0 0 0 0 7,8,9 N 0 0 P F default a:5:{s:16:"min_items_in_box";i:1;s:16:"max_items_in_box";i:100;s:10:"box_length";i:4;s:9:"box_width";i:3;s:10:"box_height";i:1;} N 1749672711 activity 0 1.000 Y D M N N
370 E-M P A 0.00 42 2.300 0 0 0 0.00 0 1511381135 N N N D N R N N N 1 Y 10 0 0 0 0 0 7,8,9 N 0 0 P A default a:5:{s:16:"min_items_in_box";i:1;s:16:"max_items_in_box";i:100;s:10:"box_length";i:4;s:9:"box_width";i:2;s:10:"box_height";i:2;} N 1751993131 activity 0 1.000 Y D M N N
3478 CA-ASC2 P A 9.95 35 2.800 0 0 0 0.00 0 1725914485 N N N D N R N N N 1 Y 10 0 0 0 0 0 7,8,9 N 0 0 P F default a:5:{s:16:"min_items_in_box";i:1;s:16:"max_items_in_box";i:100;s:10:"box_length";i:3;s:9:"box_width";i:3;s:10:"box_height";i:3;} N 1749657788 activity 0 1.000 Y D M N N