SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db60e864a6f24290c5999c724bfacfdde2ac15b76e35f7d11e028737b606aa75' 
  AND token = 'GT5HomXnAGd5s4FrTsYOYslUxAUbatlxFVoBKqC/RIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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