SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b844a45c32d1fd99f9da7813d3f70ab86b1a6418fa1534aa6bc5d768e3aa586' 
  AND token = 'ehXpkePfLnlwULKSqSVJd5wOsrUpkhGBSv2f6Wq34uQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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