SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8f9ce647107fa49014d7443cf91241cc8b0691ab2ec30f5ec007a1d3f9b143e' 
  AND token = 'Xklw55XTNqrxbT/Wsc5SGxBTN+Jjv0dpZxxmKG+QIoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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