SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a88c27755044d4c3188aa6f9506d79eb8b7adc82b6afaaeaae7b2a3efad3b80' 
  AND token = 'bVDDya91ZJWVxWe3s1HDEj69BFFilmvL4DL8VkkAP1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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