Sandbox

SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = 'Z51J-BWUM-OUPZ-PFEB-8F90-M87D-RAK3-GQIR' 
  AND product_id = 166 
  AND expires_at > 1778209921 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00026

JSON explain

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