SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73f2099bab25dbaa87af04eba67b9522c895f4f3a55b501542cf7d89ca4ac86d' 
  AND token = 'f+rXdj0k7bKgWX/QOYsz+2xiJRrTxudZAY3KcvKmX1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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