SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40da49d3ce178d0968f8f6b5b91283bd4a4d7bfe1d7ad0d429b192ab9d0c85b5' 
  AND token = 'EqELj0o36hooRJsw+VKXpNFEQWcMayeXWK59SfJbOgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}