SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    8819, 8453, 8632, 7831, 7167, 8027, 7694, 
    12087, 12088, 12089, 12090, 12084, 
    12085, 12086, 18675, 18680, 18610, 
    18611, 18612, 18633, 18553, 18491, 
    18492, 18493
  )

Query time 0.00138

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_warehouses_sum_products_amount",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 25,
      "filtered": 100,
      "index_condition": "cscart_warehouses_sum_products_amount.product_id in (8819,8453,8632,7831,7167,8027,7694,12087,12088,12089,12090,12084,12085,12086,18675,18680,18610,18611,18612,18633,18553,18491,18492,18493)"
    }
  }
}

Result

product_id amount
7167 1
7694 16
7831 1
8027 3
8453 40
8632 2
8819 43
12084 10
12085 6
12086 7
12087 5
12088 3
12089 4
12090 5
18491 2
18492 3
18493 1
18553 1
18610 1
18611 2
18612 1
18633 4
18675 6
18680 2