SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    51033, 51026, 51035, 51059, 51069, 51070, 
    51038, 51066, 51023, 51041, 51056, 
    51040, 51050, 51065, 51039, 51052, 
    51009, 51034, 51061, 51036, 51037, 
    51068, 51064, 51055, 51058, 51071
  )

Query time 0.00088

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "27.66"
    },
    "table": {
      "table_name": "cscart_warehouses_sum_products_amount",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 47,
      "rows_produced_per_join": 47,
      "filtered": "100.00",
      "index_condition": "(`test_uchur_k`.`cscart_warehouses_sum_products_amount`.`product_id` in (51033,51026,51035,51059,51069,51070,51038,51066,51023,51041,51056,51040,51050,51065,51039,51052,51009,51034,51061,51036,51037,51068,51064,51055,51058,51071))",
      "cost_info": {
        "read_cost": "22.96",
        "eval_cost": "4.70",
        "prefix_cost": "27.66",
        "data_read_per_join": "752"
      },
      "used_columns": [
        "product_id",
        "amount"
      ]
    }
  }
}

Result

product_id amount
51009 3
51009 3
51023 5
51023 5
51026 5
51026 5
51033 1
51033 1
51034 1
51034 1
51035 1
51035 1
51036 1
51036 1
51037 1
51037 1
51038 1
51038 1
51039 1
51039 1
51040 2
51040 2
51041 5
51041 5
51050 5
51050 5
51052 2
51052 2
51055 5
51055 5
51056 2
51056 2
51058 3
51058 3
51059 20
51059 20
51061 5
51061 5
51064 5
51064 5
51065 5
51065 5
51066 5
51066 5
51068 3
51068 3
51069 2
51069 2
51070 2
51070 2
51071 15
51071 15