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 (
    394196, 431190, 430574, 431092, 431106, 
    431147, 430849, 431162, 431128, 431099, 
    431132, 431202, 430637, 430639, 431096, 
    431168, 431141, 431153, 431137, 431155, 
    431033, 431130, 430911, 430640, 431134, 
    431125, 431154, 431090, 431146, 431065, 
    431067, 431187, 431048, 431094, 430697, 
    430767, 431050, 431104, 430745, 431124, 
    431117, 431191, 431157, 431160, 430681, 
    431116, 430743, 430850, 430908, 431084, 
    431107, 430998, 431026, 430655, 430744, 
    431100, 431115, 430915, 430916, 430636, 
    430924, 431195, 430747, 430803, 431176, 
    431203, 430748, 431204, 431133, 430648, 
    431196, 430823, 431158, 431199, 431122, 
    430903, 430848, 431139, 430831, 431150, 
    430665, 430696, 431145, 431102, 430771, 
    430907, 430649, 430646, 430647, 430912, 
    430935, 430638, 430766, 431097, 431151, 
    430821, 430824, 431359, 430857, 431201
  ) 
  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 0.00223

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 (394196,431190,430574,431092,431106,431147,430849,431162,431128,431099,431132,431202,430637,430639,431096,431168,431141,431153,431137,431155,431033,431130,430911,430640,431134,431125,431154,431090,431146,431065,431067,431187,431048,431094,430697,430767,431050,431104,430745,431124,431117,431191,431157,431160,430681,431116,430743,430850,430908,431084,431107,430998,431026,430655,430744,431100,431115,430915,430916,430636,430924,431195,430747,430803,431176,431203,430748,431204,431133,430648,431196,430823,431158,431199,431122,430903,430848,431139,430831,431150,430665,430696,431145,431102,430771,430907,430649,430646,430647,430912,430935,430638,430766,431097,431151,430821,430824,431359,430857,431201)) and (`webmarco`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}