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 (
    1909, 1136, 1135, 1134, 1133, 1132, 1131, 
    1130, 1129, 1128, 1127, 1126, 1125, 
    1124, 1123, 1111, 1110, 1109, 1108, 
    1107, 1102, 1101, 1099, 1096, 1094, 
    1092, 1088, 1054, 1053, 1051, 1050, 
    1049, 1048, 967, 966, 965, 964, 963, 
    962, 960, 959, 958, 957, 956, 955, 954, 
    953, 952, 951, 950, 949, 948, 947, 946, 
    945, 944, 943, 942, 941, 940, 939, 938, 
    937, 936, 935, 932, 931, 930, 929, 928, 
    927, 919, 918, 917, 517, 516, 515, 478, 
    477, 476, 475, 474, 464, 460, 434, 433, 
    432, 431, 428, 427, 424, 423, 422, 421, 
    420, 419
  ) 
  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 0.00170

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "67.66"
    },
    "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": 97,
        "rows_produced_per_join": 19,
        "filtered": "19.94",
        "index_condition": "(`wearethehelpful_scalesta_net`.`cscart_product_prices`.`product_id` in (1909,1136,1135,1134,1133,1132,1131,1130,1129,1128,1127,1126,1125,1124,1123,1111,1110,1109,1108,1107,1102,1101,1099,1096,1094,1092,1088,1054,1053,1051,1050,1049,1048,967,966,965,964,963,962,960,959,958,957,956,955,954,953,952,951,950,949,948,947,946,945,944,943,942,941,940,939,938,937,936,935,932,931,930,929,928,927,919,918,917,517,516,515,478,477,476,475,474,464,460,434,433,432,431,428,427,424,423,422,421,420,419))",
        "cost_info": {
          "read_cost": "65.73",
          "eval_cost": "1.93",
          "prefix_cost": "67.66",
          "data_read_per_join": "464"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`wearethehelpful_scalesta_net`.`cscart_product_prices`.`lower_limit` = 1) and (`wearethehelpful_scalesta_net`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}