SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2584c444c46dd74a8b4fed65eb1593236b4a9d59d4df3658a85f97dd2182c66' 
  AND token = 'SLvBVFiItJvzqAarpZN5zUPha5DnokpTkSku59koHVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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