SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec3910e7ae2359e26bed3e0db28320a8b405c734cf89cef505ef8067c56d6ead' 
  AND token = '8tXjWmClVwMU5m1IQJmId/Wnh6gHCp4rGiQFiDz3Bwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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