SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '947b10c9185b84979cf8a9d0611b5fcec83b49295cae5d49210eb2d4a7e68a57' 
  AND token = '2QrtnVauhg/O3G8vM+A1nYy5zUZK7YIp2ZBonwfIPsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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