SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (136, 138, 139)

Query time 0.00035

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_products range PRIMARY PRIMARY 3 3 Using index condition

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 buy_now_url units_in_product show_price_per_x_units product_label_id product_label_id_by_admin
136 A0136VBI1A P A 1 0.00 0 0.000 0 0 0 0.00 0 1328644800 1697804132 0 N N N N Y N N Y 10 0 B 6 N 0 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;} 0 0.000 1.000
138 G0138IU32J P A 1 0.00 0 0.000 0 0 0 0.00 0 1328644800 1697804132 0 N N N N Y N N Y 10 0 B 6 N 0 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;} 0 0.000 1.000
139 Z0139588PS P A 1 0.00 0 0.000 0 0 0 0.00 0 1328644800 1697804132 0 N N N N Y N N Y 10 0 S 6 N 0 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;} 0 0.000 1.000