SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31f19758e85dbce8bd3bdd5e95300fb20ca1111e0cb6d691c1534d7716b27335' 
  AND token = 'hwCQtJhUWfNJbJqvbUwEOaDKhRj07ja+8kGdgW0YZzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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