SELECT 
  cscart_product_prices.product_id, 
  COALESCE(
    cscart_master_products_storefront_min_price.price, 
    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 
  LEFT JOIN cscart_master_products_storefront_min_price ON cscart_master_products_storefront_min_price.product_id = cscart_product_prices.product_id 
  AND cscart_master_products_storefront_min_price.storefront_id = 1 
WHERE 
  cscart_product_prices.product_id IN (
    143574, 154235, 157361, 133193, 132858, 
    132112, 121316, 166649, 161383, 156616, 
    169021, 155568, 129545, 143889, 157865, 
    158465, 119733, 157747, 135156, 141356, 
    170940, 153217, 141168, 139111, 152784, 
    127480, 165385, 161916, 175582, 151286, 
    118370, 131161
  ) 
  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 0.01265

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.13249358,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_prices",
          "access_type": "range",
          "possible_keys": [
            "usergroup",
            "product_id",
            "lower_limit",
            "usergroup_id",
            "wdbi_product_id_lower_limit_usergroup_id_price_eff1727beeef",
            "wdbi_usergroup_id_lower_limit_product_id_92b7e8f6a250",
            "wdbi_product_id_lower_limit_usergroup_id_price_perc_3b2301d551d0",
            "wdbi_lower_limit_usergroup_id_product_id_b93629431718"
          ],
          "key": "usergroup",
          "key_length": "9",
          "used_key_parts": ["product_id", "usergroup_id", "lower_limit"],
          "loops": 1,
          "rows": 64,
          "cost": 0.11207368,
          "filtered": 20,
          "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.product_id in (143574,154235,157361,133193,132858,132112,121316,166649,161383,156616,169021,155568,129545,143889,157865,158465,119733,157747,135156,141356,170940,153217,141168,139111,152784,127480,165385,161916,175582,151286,118370,131161) and cscart_product_prices.usergroup_id in (0,1)"
        }
      },
      {
        "table": {
          "table_name": "cscart_master_products_storefront_min_price",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "8",
          "used_key_parts": ["product_id", "storefront_id"],
          "ref": [
            "u985510652_ecartify_abhi.cscart_product_prices.product_id",
            "const"
          ],
          "loops": 12.8,
          "rows": 1,
          "cost": 0.012268032,
          "filtered": 100,
          "attached_condition": "trigcond(cscart_master_products_storefront_min_price.product_id = cscart_product_prices.product_id)"
        }
      }
    ]
  }
}