SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff5556b8b3c5676b5910fff5a370f9711c37211e9f6e695a1894fe93d184c7cd' 
  AND token = 'ZxNBxW2wYMh2BKtUho5GKhCjhTAwfDYJbNFXQRoTkQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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