SELECT 
  1 
FROM 
  cscart_june_setupec_print_temp_designs 
WHERE 
  session_id = 'SR28-2M0H-69RQ-NPNK-NR3H-ZX4I-8AGZ-0FLQ' 
  AND product_id = 34 
  AND expires_at > 1781766442 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00035

JSON explain

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