SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a641c91b88d68e0a5c7643f67a636473fc1adb83ba2df621d8504e8e9c102c9' 
  AND token = 'mNdcuUJXjxoIPFdBZLD33p/oVTbihwDSwAlTuCXzNM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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