SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '504fd9429d0db06de5ecc01093272c43ca5990ed34a59fde764f466a18fdc59f' 
  AND token = 'eCleOi5iGfUfHRQRVJl7HCcrR84jsrWtTJtlnWt/7qU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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