SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = 'P0JL-2RX9-A59O-FRH6-G91F-QN52-T3CY-E3H6' 
  AND product_id = 44 
  AND expires_at > 1777394458 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00034

JSON explain

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