SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ce9cb28e23d43c180c48943e5a2b32d5b170c06890f3a70af99f5e958d15aea' 
  AND token = 'mAiUd8iFm9fgZp8ShEtxI/9XMqZecdKJ7qab8PsPe+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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