SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc6bc1b39dc64c2495845668a002647562864bf8bcb0d8adbd6adba6520faf53' 
  AND token = 'luzyNv4ZLnhhRMuzguBQfa4vkSejFfS7ZDWe2VH6WA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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