SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f140291e710750ab8a6411d8d05c4425d54308f98b7fa0d0fa96655cae9b6db3' 
  AND token = '2FupkY8sXo9zX2+YA4FvQ/K+/KMYyuRnLigLkZpF/5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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