SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8726c788aa17d2dd5d1bbda38f7fe43784f745c325bb808ef7d03df3e29477fc' 
  AND token = 'D7dl36K74SGqTT2wHFIxjd3FSVVqq1RQMYq8K/rZhIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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