SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30d0a507b0dc87df1d4d10fa076b085d6b1fd6ab7644f0b1446151ade7510f4d' 
  AND token = 'UdjLsggNqOKbHwKhKKETUlEtKOOB2Yuz3cLfXtD6uQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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