SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7891175a96725402dcb49d2d5e6ba0ed098075939c48dfba1eadcf414c29a8a9' 
  AND token = 'VMVPrfXbJCCtUbF8msMqGu1gn7ZqZnGDe0caSuPsQIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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