SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cffb97a57b9140c9a45bf92b16ae9af61aff5e51ad2973197502df83ed5a6e08' 
  AND token = 'Q4IQDUcHtRpMGUYAFt71ZmVU7uilO95Repfo2LE7je0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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