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 (
    1925, 1926, 1927, 1928, 1929, 1930, 1931, 
    5560, 5561, 5562, 5563, 5564, 5565, 
    5566, 5567, 5568, 5569, 5570, 5571, 
    5572, 5573, 5574, 5575, 5576, 5577, 
    5578, 5579, 5580, 5581, 5582, 5583, 
    5584, 5585, 5586, 5587, 5588, 5589, 
    5590, 5591, 5592, 5593, 5594, 5595, 
    5596, 5597, 5598, 5599, 5600, 5601, 
    5602, 5603, 5604, 5605, 5606, 5607, 
    5608, 5609, 5610, 5611, 5612, 1423, 
    1424, 1425, 1426, 1427, 5136, 5137, 
    5138, 5139, 5140, 5141, 6711, 1455, 
    5164, 1445, 5154, 1456, 5165, 1446, 
    5155, 1458, 5167, 1448, 5157, 1459, 
    5168, 5158, 1820, 1821, 1822, 1823, 
    1824, 1825, 1826, 1827, 1828
  ) 
  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 0.00212

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "67.21"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "cscart_product_prices",
        "access_type": "range",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "key": "product_id",
        "used_key_parts": [
          "product_id"
        ],
        "key_length": "3",
        "rows_examined_per_scan": 96,
        "rows_produced_per_join": 19,
        "filtered": "20.00",
        "index_condition": "(`gaseus`.`cscart_product_prices`.`product_id` in (1925,1926,1927,1928,1929,1930,1931,5560,5561,5562,5563,5564,5565,5566,5567,5568,5569,5570,5571,5572,5573,5574,5575,5576,5577,5578,5579,5580,5581,5582,5583,5584,5585,5586,5587,5588,5589,5590,5591,5592,5593,5594,5595,5596,5597,5598,5599,5600,5601,5602,5603,5604,5605,5606,5607,5608,5609,5610,5611,5612,1423,1424,1425,1426,1427,5136,5137,5138,5139,5140,5141,6711,1455,5164,1445,5154,1456,5165,1446,5155,1458,5167,1448,5157,1459,5168,5158,1820,1821,1822,1823,1824,1825,1826,1827,1828))",
        "cost_info": {
          "read_cost": "65.29",
          "eval_cost": "1.92",
          "prefix_cost": "67.21",
          "data_read_per_join": "460"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`gaseus`.`cscart_product_prices`.`lower_limit` = 1) and (`gaseus`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}