SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99a993068530946ff0674e8db7ba81eb652dd526bd51964794799928261e5aae' 
  AND token = 'VYBqWCDKQIAAUs7nmZOsHcm4Xu3dqPuHjJtpdIVhJDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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