SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bbeaea1e4a24142df837fb5fb978eccbd58318460ce09b6d6e9f416b19ea210' 
  AND token = 'Zt3qPnIMSEVakOru65axFjAArYvA4DZQFVEqc8jswnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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