SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '327f46ce45bf0f67812701e0e9c76d37489ea2bbf289043028ce4ae4b33de5e0' 
  AND token = '7EakYydvspPhZnxPRxVA4neNUvBPRBfx4WTcnem80do=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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