SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e8494c4e493eba79e725d86fbfabf8a04db5a91142825bb73d2a49560b2221' 
  AND token = 'Hz3TlAwdUpHUmcF15Kx4CCmNA1zNLX9MzzuvnqnZEtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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