Sandbox

SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = 'A1XV-P3OZ-NTQY-VZ12-ZRPN-HKZJ-3XKF-8VQG' 
  AND product_id = 126 
  AND expires_at > 1778097972 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00035

JSON explain

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