SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa4302e3401d38d3298386da54a8777db2ad53df13ff7fa924f475bbf2be0a85' 
  AND token = '1BElSlvyMqp/HoZ8JpYy7spCjHjnOWWqttAuTUxfNrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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