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 (
    9314, 9341, 9368, 9374, 9375, 9397, 9408, 
    9481, 9504, 9505, 9525, 8997, 9126, 
    9149, 9150, 9154, 9155, 9158, 9178, 
    9186, 9191, 9240, 9242, 9284, 9285, 
    9315, 9316, 9317, 9319, 9336, 9338, 
    9343, 9347, 9352, 9359, 9366, 9379, 
    9385, 9387, 9392, 9398, 9401, 9402, 
    9407, 9410, 9414, 9415, 9419, 9420, 
    9426, 9427, 9478, 9479, 9480, 9482, 
    9498, 9501, 9513, 9518, 9524, 8996, 
    8998, 9021, 9031, 9112, 9156, 9180, 
    9218, 9243, 9283, 9289, 9294, 9335, 
    9339, 9340, 9344, 9348, 9351, 9353, 
    9355
  ) 
  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 0.00204

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "56.01"
    },
    "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": 80,
        "rows_produced_per_join": 15,
        "filtered": "19.99",
        "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_prices`.`product_id` in (9314,9341,9368,9374,9375,9397,9408,9481,9504,9505,9525,8997,9126,9149,9150,9154,9155,9158,9178,9186,9191,9240,9242,9284,9285,9315,9316,9317,9319,9336,9338,9343,9347,9352,9359,9366,9379,9385,9387,9392,9398,9401,9402,9407,9410,9414,9415,9419,9420,9426,9427,9478,9479,9480,9482,9498,9501,9513,9518,9524,8996,8998,9021,9031,9112,9156,9180,9218,9243,9283,9289,9294,9335,9339,9340,9344,9348,9351,9353,9355))",
        "cost_info": {
          "read_cost": "54.41",
          "eval_cost": "1.60",
          "prefix_cost": "56.01",
          "data_read_per_join": "383"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_prices`.`lower_limit` = 1) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}