SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27ef580350faa30aa2e647cf537609205cf07542219743ac058dc5c3d9d9176e' 
  AND token = '042XHOY3BFUMZGogBged2o2MBOhBARM5SuyqNRnhtSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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