SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '925c47ceb61069e6dd57682d3373d1a5610139ce80f1e4a967286f47027eea35' 
  AND token = 'xawZZcy0Bxo4XunJHQPRoKCnkORqRaHzzR1S4gUyI3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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