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SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    276663, 276664, 276665, 276666, 276667, 
    276668, 276669, 276670, 276671, 276672, 
    276673, 276674, 276675, 276676, 276677
  )

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}