SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '833a4d9f467e8b51aadda0afe823651b8dddb508d5db8fefd2c409d4fe490e6a' 
  AND token = 'qDbIaLUavixu7fJcl29fQZWhZsIuWQY4NbTlu5MSGg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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