SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = '0ZKI-8QHV-C7P5-JF07-E8K8-K9BR-H24Q-SG5K' 
  AND product_id = 232 
  AND expires_at > 1777128718 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00021

JSON explain

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