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 (
    79, 80, 81, 82, 140, 141, 142, 143, 144, 
    145, 146, 161, 162, 163, 164, 165, 166, 
    167, 243, 244, 245, 246, 247, 248, 249, 
    297, 298, 299, 300, 301, 302, 3525, 3526, 
    3527, 3528, 3529, 3530, 3531, 3940, 
    3941, 3942, 3943, 3944, 3945, 3946, 
    3985, 3986, 3987, 3988, 3989, 3990, 
    3991, 4045, 4046, 4047, 4048, 4049, 
    4050, 4051, 4128, 4129, 4130, 4131, 
    4132, 4133, 4134, 4181, 4182, 4183, 
    4184, 4185, 4186, 4187, 26, 27, 28, 72, 
    73, 74, 75, 133, 134, 135, 136, 137, 138, 
    139, 240, 241, 242, 293, 294, 295, 296, 
    3520, 3521
  ) 
  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 0.00153

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 (79,80,81,82,140,141,142,143,144,145,146,161,162,163,164,165,166,167,243,244,245,246,247,248,249,297,298,299,300,301,302,3525,3526,3527,3528,3529,3530,3531,3940,3941,3942,3943,3944,3945,3946,3985,3986,3987,3988,3989,3990,3991,4045,4046,4047,4048,4049,4050,4051,4128,4129,4130,4131,4132,4133,4134,4181,4182,4183,4184,4185,4186,4187,26,27,28,72,73,74,75,133,134,135,136,137,138,139,240,241,242,293,294,295,296,3520,3521))",
        "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)))"
      }
    }
  }
}