SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '200ef6411f278870bc25ddaf59769a7561633df0c18cb8f2f4baa064e9f055d3' 
  AND token = 'q8Zt1LtoNk4zXOC+3kLOAxkFGgZF0qyZuUqhQXv9Mtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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