SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = 'WE4G-2U89-503B-R6LG-AZUU-MEU8-GGR7-1OED' 
  AND product_id = 102 
  AND expires_at > 1777133772 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00027

JSON explain

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