SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = 'D2SV-YF0E-TSBM-VN8V-A39R-BD1A-TLRM-8SNO' 
  AND product_id = 281 
  AND expires_at > 1777995325 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00055

JSON explain

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