SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c977bee2dc85eacfdbebcaa0c869c086372c67f7ebba8c13fbad8197e794e096' 
  AND token = '4oFKhn7fYzJYlpMsxbJz13DbgmzTMNdfBgTZ5tMtEyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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