SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24540a75881469fa37270615192a55abf30fe3b4c8850b473300f123a3e70a05' 
  AND token = 'klAN187ShDsiKHvANNpIWhl6MwC3nAwqDwi6ELIBHyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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