SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    51412, 51500, 51460, 51457, 51464, 51530, 
    51053, 51501, 51051, 51510, 51551, 
    51486, 51478, 51469, 51531, 51461
  )

Query time 0.00066

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "17.51"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "index_condition": "(`test_uchur_k`.`cscart_warehouses_sum_products_amount`.`product_id` in (51412,51500,51460,51457,51464,51530,51053,51501,51051,51510,51551,51486,51478,51469,51531,51461))",
      "cost_info": {
        "read_cost": "14.51",
        "eval_cost": "3.00",
        "prefix_cost": "17.51",
        "data_read_per_join": "480"
      },
      "used_columns": [
        "product_id",
        "amount"
      ]
    }
  }
}