SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af2b379bd8a105837ba963eb0ddcdcf009646af02368e92bf0eb902b6f140f2c' 
  AND token = 'Nw/Kf76UfWuUmHy/qnvJeebHAnDRtNsFxXYxaKtuo4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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