SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '745df7b1b7811ccd9ebb9fa2b7b27a65638f025a989c7bd13bc5c9fe3b39e2a2' 
  AND token = 'uZS8IDBUt+qpn7fuiJWQFPycrLhCvFoOA1MQoeazRrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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