SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = 'XZ47-G8R9-0OKW-JIE2-FC5S-MWU3-T1HF-ADAQ' 
  AND product_id = 103 
  AND expires_at > 1778209921 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00029

JSON explain

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