SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b461171889e8e88ba4674bc48ee80332a57b5e576a3a6f2b583de798435cee6' 
  AND token = 'yIZQwHvh+ckHpsJKTYOXqfCWNJlNeJ4IICWCytTDTqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}