SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be3f28cdb77a34e0bf68498a4eb7d38b08c8574cf0c9da834fd521bf2b936dea' 
  AND token = '0flGWyOMC/TELz6X71DK9wgTvr0i+uxmWTf0UdhpPyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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