SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd77c44d7df9e491d633b13d79d7608b721a994c2d7edc6af6392333262ddf33' 
  AND token = 'GS+H2g5hhzhF2fu2PZjCFbSGaabZpRXDeYonxPiPyww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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