SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae0429d5b630a2da75d48cea12037d043252ef3aa41581adfd63d9c9c49e8222' 
  AND token = 'rD3qPjklK+tzhJUQoLIrkW1K2W8I9qGWEDQwzyQrUMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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