SELECT 
  cscart_product_prices.product_id, 
  MIN(
    IF(
      cscart_product_prices.percentage_discount = 0, 
      cscart_product_prices.price, 
      cscart_product_prices.price - (
        cscart_product_prices.price * cscart_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  cscart_product_prices 
WHERE 
  cscart_product_prices.product_id IN (
    357038, 358186, 350654, 350889, 351111, 
    359307, 355184, 357857, 350727, 354634, 
    357680, 350718, 355245, 358130, 358146, 
    359166, 351020, 355292, 357278, 359195, 
    359388, 350728, 350801, 357311, 357839, 
    359272, 359313, 351692, 354594, 357977, 
    357996, 358128, 359146, 357042, 358216, 
    350872, 351492, 352774, 351516, 355179, 
    355205, 352287, 357172, 351056, 358166, 
    350828, 350900, 350942, 351017, 357299, 
    357850, 359169, 353933, 357041, 357069, 
    350768, 350823, 350887, 350923, 351129, 
    356169, 357053, 357750, 358206, 350635, 
    351514, 352292, 351499, 354909, 355214, 
    355331, 357099, 351171, 351655, 357257, 
    351219, 356141, 357847, 351041, 351045, 
    356934, 357933, 359097, 351006, 351669, 
    351702, 354910, 355213, 350670, 350809, 
    353938, 357717, 351712, 350755, 351167, 
    351482, 354938, 355301, 357755, 357764
  ) 
  AND cscart_product_prices.lower_limit = 1 
  AND cscart_product_prices.usergroup_id IN (0, 1) 
GROUP BY 
  cscart_product_prices.product_id

Query time 0.00145

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "280.31"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "cscart_product_prices",
        "access_type": "range",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "key": "usergroup",
        "used_key_parts": [
          "product_id",
          "usergroup_id",
          "lower_limit"
        ],
        "key_length": "9",
        "rows_examined_per_scan": 200,
        "rows_produced_per_join": 200,
        "filtered": "100.00",
        "cost_info": {
          "read_cost": "240.31",
          "eval_cost": "40.00",
          "prefix_cost": "280.31",
          "data_read_per_join": "12K"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`webmarco`.`cscart_product_prices`.`lower_limit` = 1) and (`webmarco`.`cscart_product_prices`.`product_id` in (357038,358186,350654,350889,351111,359307,355184,357857,350727,354634,357680,350718,355245,358130,358146,359166,351020,355292,357278,359195,359388,350728,350801,357311,357839,359272,359313,351692,354594,357977,357996,358128,359146,357042,358216,350872,351492,352774,351516,355179,355205,352287,357172,351056,358166,350828,350900,350942,351017,357299,357850,359169,353933,357041,357069,350768,350823,350887,350923,351129,356169,357053,357750,358206,350635,351514,352292,351499,354909,355214,355331,357099,351171,351655,357257,351219,356141,357847,351041,351045,356934,357933,359097,351006,351669,351702,354910,355213,350670,350809,353938,357717,351712,350755,351167,351482,354938,355301,357755,357764)) and (`webmarco`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}