SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ed54f0ba7a6d55125df1b9847164600d02486cfbe2de0a2e75598ac9916f72e' 
  AND token = 'FbJbOkf0UGkUwrxUORlMZzxwGO/D+eUQUCBXHXbAqsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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