SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cdfef85dde8cda7db96215c16fb0b6a541307e4c63f697d61a8bba5ba82db84' 
  AND token = 'oq90ptaXx++w+ohPnKREC8RSSadegXNp3Nza7wZ/iNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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