SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e374b871355c9bba45d0fd053d6d25268c9c2210196618cb84fca134eda13673' 
  AND token = 'c/eF/tFQuovBWgTI1QzdtjvHW0HNElJMQa0XD7OUm6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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