SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f96d4386442e48f092a490ee4462c56c90a567ee70769f1517063f5c3aa5bf5' 
  AND token = 'tURCFafFDMLPqP6KFZlJR4orxxw/ueGAYA+henA4bi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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