SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '731de63ce1476709054e8a8bf68ea2a654fd548c6057a6a98de0d81d87b1b9ee' 
  AND token = 'XGPX8npWmHwztfvHyz4CFELUgQ3k9qR+6dwk+WKhhEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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