SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = '21KI-1DRV-9X7M-7V97-4RIJ-XEK7-3UI4-H8KA' 
  AND product_id = 33 
  AND expires_at > 1777396036 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00034

JSON explain

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