SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d76bf5860be2f2713983045944146ff8c6431712cae9c92a45a138c9713870f' 
  AND token = 'ZMJLbYwxUl6qylGBgu9hjpQDzTGl6xhm5KDznairvMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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