SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df3fdb7a1a62dc2f93fd10097787b74dff57b3e0ba8304412cb754f7d71f1e44' 
  AND token = 'gKhv7WZEnt8Rx2YC0rCSYsKlRrfAcBT56eVv2Jmg1Wg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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