SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a949aac8cb631506fe76ea1f2c36a289547b63bb0914e66f6d0a6b76807a7b11' 
  AND token = 'xx5nGKoIXekW3hKCmcbnouss51Bl2XnDhlHPlaeEfCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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