SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fbb53e811737208b5ba9b821f72d19d66f943e05db4bc42efd102597f9bd831' 
  AND token = 'RJXoY9Bt68ZF3dmC/Z1X70vNQZFg6uPC4F2UMXYwuZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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