SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53281d0ef8d65fe761fe8772c9ac675e68390f2dbbe8c9a4719edb10fabc12d1' 
  AND token = 'SHgJET4FxJNhRB5hOl47XhyJysF4QbunBN77ADhzfFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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