SELECT 
  1 
FROM 
  cscart_june_setupec_print_temp_designs 
WHERE 
  session_id = 'CG6A-G40I-BG05-Z12A-TZZZ-50T1-11OK-4K63' 
  AND product_id = 43 
  AND expires_at > 1781897452 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00025

JSON explain

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