SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd28e8a429d810cf3f1683d40ba40b76cbf770121619fa29256e4bef6764b8ca4' 
  AND token = 'd/RU6wJdMuZSVzhZXZbBCuckHJrocy7yX3PRqBUOUAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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