SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e30a87c7d328e9177baf0262b0fade4accb3decac5036b09e95cefd3d7a37a4' 
  AND token = 'Cs8IcWXHG93GhTtDqKIZlR1bKfQxMTNRumayZMmDrqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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