SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12ab28a882470019083ec05b4960838bdbf1a31ffe138c1d58cdb393189bf6c6' 
  AND token = 'rHqsYCIcytA4TZ4OYkxeVCJ4oFAl+H8mzUFcg9vvPhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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