SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '146c5610a4925ac80fb4d54aed696391159415accaa6b09b6bd93eb8fc9f50e1' 
  AND token = 'x2audvrs1Waz1hwNhFQEeONBm7BXwJRzTE5bV+Mpr8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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