SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '597b6604684a7a816744c259c36db13a4e9710f35a549fb05e95d3719f83f231' 
  AND token = 'I7WH/DyyLZrK5gBX6b9ITTxVlCUzYi8L0+uILHKhZ/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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