SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '117e6735fed3dc8914e9a8b6e6301a6b5682554caff74912fb124f03d6f8cb80' 
  AND token = 'oJ6iuoGE3hJ0mr6Fca0meHwqZTlDKjfc+ZlV8BLgt48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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