SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b5932bfcaca20683ab4e4dbdab40f2a5dc7b3427a3a7cd0fbebbc84d484e29b' 
  AND token = 'ygAvPGdRAfvaWNSmv5fevN3QgroMrE5mKUdKzmBmeFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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