SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abe5b4d79017b2f6e973c2998274b63f588e1a17d7f3bf0dbfb6c52df4c06668' 
  AND token = 'hmUfw3+P7xkWw23xMVvAVsUWpT9hBZQj+DyKLha9pIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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