SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f82379654fb3071851621a23911308404f9117611db19041dbf8ace6b6598344' 
  AND token = 'uSMzlVnazOUgAEpDD2/mvnTlyfQZxlLM8ee6EgY3Yjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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