SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76cac2e30d7bcadce426b8ca326c782e8363bb7c54ceb04cc66ccafb21c815b5' 
  AND token = 'lLDL+nMLzYv8ECwFrTNznpSgmLG25NREwkKhJoAIKfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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