SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '037f29589716df551d599d8ef2c4bbcf3780401199d252406cf883ad1fd051ea' 
  AND token = 'l3sTJ/R44zzmEGUc+vVOfGZAJo027QzgOYz7pRUorN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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