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 (
    5795, 5796, 5797, 5798, 6307, 6308, 6309, 
    6310, 6311, 6357, 6358, 6359, 6360, 
    6361, 6362, 6363, 6364, 6365, 6431, 
    6432, 6433, 6434, 6435, 6436, 6437, 
    6438, 6439, 6440, 6441, 6442, 6443, 
    6444, 6445, 6446, 6447, 6526, 6527, 
    6528, 6529, 6530, 6531, 6532, 6533, 
    6534, 6615, 6616, 6617, 6618, 6619, 
    6620, 6621, 6622, 2272, 2273, 2274, 
    2275, 2276, 2340, 2341, 2342, 2343, 
    2344, 2345, 2346, 2347, 2348, 2421, 
    2422, 2423, 2424, 2425, 2426, 2427, 
    2428, 2429, 2430, 2431, 2432, 2433, 
    2434, 2435, 2436, 2437, 2438, 2519, 
    2520, 2521, 2522, 2523, 2524, 2525, 
    2526, 2527, 2608, 2609, 2610
  ) 
  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 0.00217

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": "19.99",
        "index_condition": "(`test2_gaseus`.`cscart_product_prices`.`product_id` in (5795,5796,5797,5798,6307,6308,6309,6310,6311,6357,6358,6359,6360,6361,6362,6363,6364,6365,6431,6432,6433,6434,6435,6436,6437,6438,6439,6440,6441,6442,6443,6444,6445,6446,6447,6526,6527,6528,6529,6530,6531,6532,6533,6534,6615,6616,6617,6618,6619,6620,6621,6622,2272,2273,2274,2275,2276,2340,2341,2342,2343,2344,2345,2346,2347,2348,2421,2422,2423,2424,2425,2426,2427,2428,2429,2430,2431,2432,2433,2434,2435,2436,2437,2438,2519,2520,2521,2522,2523,2524,2525,2526,2527,2608,2609,2610))",
        "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": "((`test2_gaseus`.`cscart_product_prices`.`lower_limit` = 1) and (`test2_gaseus`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}