SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '389b2d8d8ca25e03702aed29b991950d81b9bb27bb34dcf9ac2589543c67d1f3' 
  AND token = 'VaB8zrzBKflGUolUVpEkwy4Y+WYwm+7GlYR721ivSRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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