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 (
    450, 451, 452, 453, 454, 455, 1932, 1933, 
    1934, 1935, 1936, 1937, 1938, 1939, 
    1940, 1941, 1942, 1943, 1944, 1945, 
    1946, 1947, 1948, 1949, 1950, 1951, 
    1952, 1953, 1954, 1955, 1956, 1957, 
    1958, 1959, 1960, 1961, 1962, 1963, 
    1964, 1965, 1966, 1967, 1968, 1969, 
    1970, 1971, 1972, 1973, 1974, 1975, 
    1976, 1977, 1978, 1979, 1980, 1981, 
    1982, 1983, 1984, 4253, 4254, 4255, 
    4256, 4257, 4258, 4259, 4260, 4261, 
    5614, 5615, 5616, 5617, 5618, 5619, 
    5620, 5621, 5622, 5623, 5624, 5625, 
    5626, 5627, 5628, 5629, 5630, 5631, 
    5632, 5633, 5634, 5635, 5636, 5637, 
    5638, 5639, 5640, 5641
  ) 
  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 0.00156

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 (450,451,452,453,454,455,1932,1933,1934,1935,1936,1937,1938,1939,1940,1941,1942,1943,1944,1945,1946,1947,1948,1949,1950,1951,1952,1953,1954,1955,1956,1957,1958,1959,1960,1961,1962,1963,1964,1965,1966,1967,1968,1969,1970,1971,1972,1973,1974,1975,1976,1977,1978,1979,1980,1981,1982,1983,1984,4253,4254,4255,4256,4257,4258,4259,4260,4261,5614,5615,5616,5617,5618,5619,5620,5621,5622,5623,5624,5625,5626,5627,5628,5629,5630,5631,5632,5633,5634,5635,5636,5637,5638,5639,5640,5641))",
        "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)))"
      }
    }
  }
}