SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1265839c539fa1f9df473ffec323582e7d975f3b763b40c0a3624577fb5247ee' 
  AND token = 'oMqFcZqG+dAYflOAsKJBx8NgOQOqD2V3IEtmG6rrKrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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