SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cfeca2dca55d0a5348196a6bc095828486d167cfd8448089a53670b38cdceb5' 
  AND token = 'k97JmsxTG/meHpRrvliWjGsouWxVmU3lRctql/hIsBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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