SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ee34dceb3e48bf9766b55c582db7504ead42e2007af04557220171b780a00d9' 
  AND token = 'k3gHkOaPU3/dNa3bK+bLcRybQv/RYjYyFkk5TxDnpgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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