SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e400647404cf7cd26b2d406a32337d0a6ebd8d1722c80d768a49eec52bcab619' 
  AND token = 'jUzJiagpfw/q4iRX+6FV6/4QL6zqho7j7WA0DGq5Z2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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